This super moist dark chocolate mousse cake combines unsweetened natural cocoa powder and dark cocoa powder for an extra rich flavor. Fill the cake with a simplified chocolate mousse and cover the whole dessert with semi-sweet chocolate ganache. If needed, you can prepare the ganache and mousse ahead of time.
My s’mores chocolate mousse inspired me to play around in the kitchen the other week. I’ve always loved chocolate mousse, back to my childhood when my mom served it as an easy (yet totally elegant) dessert on the holiday table. Chocolate mousse is simple divinity in its own right, but when paired with chocolate cake, it’s downright decadent.
I made this chocolate mousse cake for my husband Kevin’s birthday. This cake basically demands a huge gathering because—trust me—you don’t want to be left alone with its temptation. It WILL call out your name each time you open the refrigerator.
Taunting you.
3 Parts to Dark Chocolate Mousse Cake
Let’s break down each component of this intensely rich cake:
- Dark Chocolate Cake: This is actually a variation of my tuxedo cake, which originated from my chocolate cake recipe. In recent years, I’ve found that replacing sour cream for some of the buttermilk gives the cake more structure.
- Chocolate Mousse: I researched simplified ways to make a fluffy chocolate mousse filling without the use of eggs or gelatin. This chocolate mousse filling combines real chocolate and homemade whipped cream. Or our whipped frosting would make a wonderful alternative filling if you don’t want to make the chocolate mousse!
- Chocolate Ganache: Top the whole cake with 2 ingredient semi-sweet chocolate ganache. You should be a chocolate ganache pro by now!
Video Tutorial: Chocolate Mousse Cake
Stick-to-the-back-of-your-fork moist. This is every chocolate lover’s dream!
Dark Chocolate Cake
Use this chocolate cake as the starting point. For a sturdier, yet moister crumb, swap some sour cream in for the buttermilk and reduce the hot liquid. The acidity in both sour cream and buttermilk is a must to properly leaven this cake. (If desired, see baking powder vs baking soda for more information.) This cake has a natural dark chocolate taste, but to deepen that flavor, use a mix of natural cocoa and Hershey’s Special Dark cocoa powder. A touch of espresso powder and hot coffee further enhances the chocolate flavor. The cake will not taste like coffee. Rather, the two add depth to the cake’s chocolate flavor.
- Why hot liquid? The hot liquid encourages the cocoa powder to bloom and dissolve. If you don’t drink coffee, you can use hot water.
You have options! You can make this cake into 2, 3, or 4 layers. I highly recommend 3 or 4 layers because there’s over 4 cups of chocolate mousse to spread inside. You can use 8 inch or 9 inch pans. The bake times are similar, see recipe notes.
A cup of chocolate chips adds even more chocolate flavor. I used 1 cup (180g) of mini semi-sweet chocolate chips in this pictured cake, but left them out in the video. They’re optional, but definitely worth the addition!!
You can also see this exact cake batter baked as three layers in both my chocolate peanut butter cake and chocolate raspberry cake (try one of those next!).
Simplified Chocolate Mousse
The chocolate mousse adds a creamy and light contrast to the dark chocolate layers. You need 6 ingredients:
- Hot Water
- Cocoa Powder – natural or dutch-process
- Melted Chocolate – use two 4-ounce chocolate baking bars found in the baking aisle
- Heavy Cream
- Confectioners’ Sugar
- Vanilla Extract
Whisk the hot water and cocoa powder together. Pour into melted chocolate. The hot water breaks up the chocolate, adding to the airy mousse consistency. Cocoa powder creates additional chocolate flavor. Fold this chocolate mixture into whipped cream—a combination of heavy cream, confectioners’ sugar, and vanilla extract.
Whipped cream + our chocolate mixture. ↑
Fold them together to make our chocolate mousse filling. ↓
Baker’s Tip: The chocolate mousse must chill in the refrigerator before using, so it’s a good idea to make it ahead of time or as the chocolate cake layers are cooling. The mousse is best cold, so I actually recommend serving the cake cold. (Additionally, the cake is much easier to assemble if the mousse is cold!)
Chocolate Ganache
I won’t go into a lot of detail about the chocolate ganache because I have a complete chocolate ganache tutorial for you! Like the chocolate mousse, it’s imperative to use pure chocolate. Wait about 20 minutes for the ganache to thicken before pouring onto the cake.
How to Assemble & Decorate Chocolate Mousse Cake
Chocolate ganache enrobes 4 cake layers and 3 mousse layers. Place bottom cake layer on your cake stand or serving plate. Using a large icing spatula, evenly cover the top with about 1.5 cups of chilled chocolate mousse. Top with 2nd cake layer and another 1.5 cups of mousse. Top with the third cake layer, then spread another 1.5 cups mousse evenly on top. (Save a large spoonful of mousse for a thin crumb coat.) Top with final 4th cake layer. Spread any remaining mousse around the sides as a crumb coat. Run a bench scraper around the cake to smooth it out. Refrigerate cake for at least 1 hour and up to 4 hours. Chocolate mousse is pretty fluffy, so the cake won’t hold its shape unless it’s properly chilled.
Pour ganache on top then run a bench scraper around the sides to smooth it out. You can serve the cake immediately or wait for the chocolate ganache to set. 🙂
What About Cupcakes?
Instead of a big cake, you can make chocolate mousse cupcakes. Use my chocolate cupcakes recipe and halve the chocolate mousse and chocolate ganache recipes below. Fill the cupcakes with chocolate mousse using my Sugar Plum Fairy Cupcakes as an example. Drizzle cooled cupcakes with ganache. Eat your heart out!
You can also use the chocolate mousse instead of pastry cream in homemade mille-feuille!
More Indulgent Chocolate Desserts
- Dark Chocolate Bread Pudding
- German Chocolate Cake
- Flourless Chocolate Cake
- Black Forest Cake
- Chocolate Lava Cakes
- Chocolate Mousse Pie
- Mint Chocolate Cake
Dark Chocolate Mousse Cake
- Prep Time: 2 hours, 30 minutes (includes chilling)
- Cook Time: 25 minutes
- Total Time: 5 hours, 55 minutes (includes cooling)
- Yield: serves 12
- Category: Cake
- Method: Baking
- Cuisine: American
Description
This super moist dark chocolate cake combines unsweetened natural cocoa powder and dark cocoa powder for an extra rich flavor. Fill the cake with a simplified chocolate mousse and cover it with semi-sweet chocolate ganache. If needed, you can prepare the ganache and mousse ahead of time. See notes.
Ingredients
- 1 and 3/4 cups (219g) all-purpose flour (spooned & leveled)
- 3/4 cup (62g) unsweetened natural cocoa powder* (see note)
- 1 and 3/4 cups (350g) granulated sugar
- 2 teaspoons baking soda
- 1 teaspoon baking powder
- 1 teaspoon salt
- 2 teaspoons espresso powder (optional)*
- 1/2 cup (120ml) canola or vegetable oil
- 2 large eggs, at room temperature
- 3/4 cup (180g) full fat sour cream, at room temperature
- 1/2 cup (120ml) buttermilk, at room temperature*
- 2 teaspoons pure vanilla extract
- 1/2 cup (120ml) hot water or coffee*
- optional: 1 cup (180g) mini or regular semi-sweet chocolate chips
- optional garnish: fresh berries and/or chocolate shavings
Chocolate Mousse
- 1/2 cup (120ml) hot water
- 1/4 cup (22g) unsweetened cocoa powder* (see note)
- two 4-ounce quality semi-sweet chocolate bars (113g each), finely chopped*
- 2 cups (480ml) heavy cream or heavy whipping cream
- 2 Tablespoons (15g) confectioners’ sugar
- 1/2 teaspoon pure vanilla extract
Chocolate Ganache
- two 4-ounce quality semi-sweet chocolate bars (113g each), finely chopped*
- 1 cup (240ml) heavy cream or heavy whipping cream
Instructions
- Preheat oven to 350°F (177°C). Grease four 8-inch or 9-inch cake pans, line with parchment paper rounds, then grease the parchment paper. Parchment paper helps the cakes seamlessly release from the pans. (If it’s helpful, see this parchment paper rounds for cakes video & post.)
- Make the cake: Whisk the flour, cocoa powder, sugar, baking soda, baking powder, salt, and espresso powder (if using) together in a large bowl. Set aside. Using a handheld or stand mixer fitted with a whisk attachment (or you can use a whisk) mix the oil, eggs, and sour cream together on medium-high speed until combined. Add the buttermilk and vanilla and mix until combined. Pour the wet ingredients into the dry ingredients, add the hot water/coffee, and whisk or beat on low speed until the batter is completely combined. Fold in the chocolate chips, if using.
- Divide batter evenly between 4 pans. Bake for 19-23 minutes. Baking times vary, so keep an eye on yours. The cakes are done when a toothpick inserted in the center comes out clean.
- Remove the cakes from the oven and set on a wire rack. Allow to cool completely in the pan. The cakes may slightly sink in the middle as they cool—that’s expected.
- As the cakes cool, prepare the chocolate mousse so it can chill and be ready at the same time as the cake layers. You can also prepare the mousse 1-2 days ahead of time. Whisk the hot water and cocoa powder together. Set aside. Melt the chopped chocolate bars in a double boiler or use the microwave. If using the microwave: place the chopped chocolate in a medium heat-proof bowl. Melt in 20 second increments in the microwave, stirring after each increment until completely melted and smooth. Pour hot water/cocoa mixture into melted chocolate and stir until thick and smooth. Set aside. Using a hand mixer or a stand mixer fitted with a whisk attachment, whip the heavy cream, confectioners’ sugar, and vanilla extract together on medium-high speed until medium peaks form, about 3-4 minutes. Medium peaks are between soft/loose peaks and stiff peaks. Pour in the chocolate mixture and using a spoon or rubber spatula, gently fold together. Avoid over-mixing which can deflate/thin out the mousse. Cover mousse and chill in the refrigerator for at least 2 hours and up to 2 days. Makes about 4.5 cups chocolate mousse.
- Assemble layers before preparing chocolate ganache: First, level the cakes if needed: using a large serrated knife, slice a thin layer off the tops of the cakes to create a flat surface. Discard (or crumble over ice cream!). Place 1 cake layer on your cake stand, cake turntable, or serving plate. Using a large icing spatula, evenly cover the top with about 1.5 cups chocolate mousse. Top with 2nd layer and evenly cover the top with 1.5 cups chocolate mousse. Top with the third cake layer, then spread another 1.5 cups mousse evenly on top. Save a large spoonful of mousse for a thin crumb coat. Top with final 4th cake layer. Spread any remaining mousse around the sides as a crumb coat. Run a bench scraper around the cake to smooth out crumb coat. Refrigerate cake for at least 1 hour and up to 4 hours. Prepare the ganache as you wait.
- Chocolate Ganache: Place chopped chocolate in a medium heat-proof bowl. Heat the cream in a small saucepan over medium heat until it begins to gently simmer. (Do not let it come to a rapid boil– that’s too hot!) Pour over chocolate, then let it sit for 2-3 minutes to gently soften the chocolate. With a metal spoon or small rubber spatula, very slowly stir until chocolate has melted and mixture is smooth. The finer you chopped the chocolate, the quicker it will melt with the cream. If it’s not melting, do not microwave it. If needed, see Troubleshooting Chocolate Ganache. Once ganache mixture is smooth, let it cool for 20 minutes at room temperature before spreading on chilled cake.
- Pour/spoon ganache on chilled cake. Smooth the top with an icing spatula and the sides with a bench scraper. Top with optional garnish such as fresh berries and/or chocolate shavings. Serve cake immediately or chill, uncovered, for up to 4-6 hours before serving. Cake can be served at room temperature or chilled.
- Cover leftover cake tightly and store in the refrigerator for 5 days.
Notes
- Make Ahead & Freezing Instructions: Prepare cake through step 4. Wrap the individual baked and cooled cake layers tightly and refrigerate for up to 2 days or freeze up to 3 months. Bring to room temperature, make mousse filling, then continue with step 6. You can prepare the chocolate mousse in advance. See step 5. You can also prepare the chocolate ganache ahead of time too. Refrigerate prepared ganache for up to 2-3 days. Bring to room temperature before spreading onto cake. Frosted cake freezes well, up to 3 months. Thaw overnight in the refrigerator, then bring to room temperature or serve cold.
- Special Tools (affiliate links): 8-inch Round Cake Pans or 9-inch Round Cake Pans | Glass Mixing Bowl | Whisk | Electric Mixer (Handheld or Stand) | Cooling Rack | Double Boiler | Cake Stand or Cake Turntable | Large Icing Spatula | Bench Scraper | Cake Carrier (for storage)
- 3 Layer Cake: You can also prepare this cake as a 3 layer cake. Divide batter between three 8-inch or 9-inch cake pans in step 1 and bake for 22-25 minutes or until a toothpick inserted in the center comes out clean. Use about 2 cups of chocolate mousse between each layer.
- Espresso Powder/Coffee: Espresso powder and coffee will not make the cake taste like coffee. Rather, they deepen the chocolate flavor. I highly recommend them both. If coffee isn’t your thing, you can leave out the espresso powder and use extra hot water instead of the hot coffee.
- Cocoa Powder: For the best dark chocolate flavor in the cake, I recommend using a blend of unsweetened natural cocoa powder (1/4 cup; 22g) and Hershey’s “Special Dark” cocoa powder (1/2 cup; 43g). Hershey’s Special Dark is actually a mix of natural cocoa powder (an acid) and dutch-process cocoa powder (a base) and it worked fine in this recipe. This recipe needs acidic natural cocoa powder, so do not use ALL dutch-process cocoa powder. For best results, use 3/4 cup (65g) natural or the blend of natural/Special Dark I used. For the chocolate mousse, you can use either unsweetened natural or dutch-process cocoa powder. (Or the Hershey’s Special Dark.)
- Why Room Temperature? All refrigerated items should be at room temperature so the batter mixes together easily and evenly. Read more about why room temperature ingredients are important. Instead of sour cream, you can use plain yogurt. The cake won’t taste as rich, but it’s a fine substitute.
- Buttermilk: Buttermilk is required for this recipe. You can make your own DIY version of buttermilk if needed. Add 1 teaspoon of white vinegar or lemon juice to a liquid measuring cup. Then add enough whole milk to the same measuring cup until it reaches 1/2 cup. (In a pinch, lower fat or nondairy milks work for this soured milk, but the cake won’t taste as moist or rich.) Stir it around and let sit for 5 minutes. The homemade “buttermilk” will be somewhat curdled and ready to use in the recipe.
- Chocolate in Mousse & Ganache: Mousse & ganache will only set if the correct chocolate is used. You can use high quality chocolate chips if needed (I prefer Ghirardelli semi-sweet chocolate chips), but I recommend using pure chocolate baking bars. You can find them right next to the chocolate chips in the baking aisle. They are sold in 4 ounce bars. I like Bakers or Ghirardelli brands.
Hi, I have 2 – 9 x 2.75 round spring form pans. Could I use these and cut the layers in half. I love all of your recipes! Thanks
Hi Joanne, You can divide this batter between three pans (see recipe notes), but there is simply too much batter to bake properly in only two pans. Divide your batter, bake two layers, and whatever batter isn’t in the oven keep loosely covered at room temperature until your pans are ready to be used again. I hope you love the cake!
Thanks so much for the quick response. I’m sure we will love the cake… we love all of Sally’s recipes ! ❤️
I made this before cutting the recipe in half and it was amazing! I am making the full four layers this time, but after one minute of whipping cream for the ganache I think it became over whipped! I had tried adding more cold cream to fix it, but it still doesn’t look smooth, any ideas why or what to do?
Hi Ali! Make sure you aren’t whipping the warm cream and chocolate together for the ganache– simply stir together until combined. We usually just use a spoon.
Hello Sally, I’m very excited to make this cake very soon cz I’m a chocolate lover and a chocolate mousse lover but my question is how did you bake your 4 pans of cake in the oven together, because the middle layer of the oven doesn’t have enough room for 4 pans or maybe you did divide them 2 by 2 in 2 layers in the oven and bake them together but Idk if that’s okay!! Please answer my question
Hi Leena, if you have more than 1 oven rack in your oven, you can bake 2 layers on each oven rack, rotating them halfway through. Or only bake 2 cakes at a time and keep the remaining batter covered at room temperature while the first 2 layers bake.
Looking forward to making this! Question about the cocoa…. my local store (Bulk Barn) had 3 choices: Cocoa Powder Superior Red 22/24%(alkalized), Black Cocoa Powder 10/12%(alkalized), and Cocoa Powder 10/12% (no additives).
Am I to use 1/4c of either of those first two in the cake and 1/2c of the last? Is there one I shouldn’t use for this?
Thanks!
Hi Erin, I can’t say for sure without testing the recipe with these exact products. I would try just as you guessed— 1/4 cup of either of the first 2 and 1/2 cup of the last.
Hi Sally,
Thank you for this recipe..it was easy to follow and the result was amazing! I made it for husbands birthday and it was a big hit. Now for my daughters birthday she wants the same cake but I need to make it with frosting ( based on the theme) I was wondering if could use this chocolate cake recipe and use your vanilla buttercream frosting for the layers as well the outer coat? Any other suggestiona?
Hi Ujwal, I’m so happy it was a hit! I recommend using the vanilla buttercream recipe from my checkerboard cake. That particular frosting recipe will yield enough frosting for this 4 layer cake.
Hi Sally, that chocolate mousse filling looks divine. ! I’m making an 8 inch, 2 layered cake and would like to use this chocolate mousse as filling. I’d like to know if the mousse filling can be precisely halved without compromising its taste and texture?
Yes, that should be just fine. Enjoy!
I made this cake for father’s day and my husband loved it! I cut the recipe in half and baked in 3x 6inch pans with no change in bake temp and time. It turned out great- cake was moist, not to sweet and not dense! This will be my go-to choc cake recipe from now on! Thanks for the fantastic recipe!
insanely good, my family says it’s the best cake they’ve ever had!
I’ve tried this whole recipe
Came out fabbbbbbb❤️
Just wanted to check sally if I don’t put mousse and fill
It with ganache would that be okay
Superb recipe ! Made this n it was a hit ! Thanks Sally
Moistest, most chocolate-y, creamiest cake you’ll ever make. Over the top combos!
Hello, how many cups of batter does this recipe yield?
About 6 cups.
Hey Sally! I’m going to attempt your chocolate mousse cake this weekend for my husband’s birthday. I’d like to incorporate hazelnuts into it (on his request). I was thinking a later of chopped hazelnuts on each layer of mousse and on top as well. What do you think? Do I need to toast the hazelnuts? Any tips? Thank you!
Hi Smita, I think hazelnuts would be a delicious addition. For enhanced flavor, you can certainly toast the hazelnuts. Let me know how he likes it!
I loved making this cake! The chocolate cake layers were super moist, the mousse smooth and creamy, and perfect ganache! It was my first time making ganache and the easy directions produced perfection! This cake is a chocolate lovers dream!!. One question- could white chocolate be substituted for making the mousse? Would love to try this cake again, but with white chocolate mousse.
I’m so happy you enjoyed it, Colette! I haven’t tested a white chocolate mousse, but you might be intereted in my tuxedo cake where I use white chocoalte ganache between the layers!
This is the best chocolate cake I’ve ever made! It’s a perfect balance of moisture and not too sweet. I used a mixture of more bitter chocolate in the ganache for contrast and I got so many compliments. Thank you so much Sally! I’ve made so many of your recipes and they’re always FANTASTIC!
My 1st time to bake a cake from scratch & oh my!!! I know a really good cake when i eat one and this recipe is a winner!!!My husband & friends said that they don’t need to go to Extraordinary Desert (my fave desert place ever) for chocolate cake anymore because this cake is amazingly delicious! Followed the recipe to the T & it was a success!
Hey, I was gonna use this cake recipe for a carving Cake. Do you know if this recipe will hold up to carving?
Hi Loire, I’m afraid this cake would be too soft and moist to hold up to carving. At this time, I don’t have a sturdy enough chocolate cake to carve.
Baked this twice, once at Thanks Giving in 2019 and for my birthday 2020 and it was a big hit. My family love it
Hi – I made the 3 (not 4 ) cakes layers yesterday, They turned out perfect, and I’m very happy about that, because I have messed up many a layer cakes, something always went wrong. So then I wrapped them in press and seal and put in fridge. This afternoon I made the Mousse, added a Tbs amaretto, hope that doesn’t mess up the texture when I go to use it between the layers tomorrow. This I also put in fridge. The on the next day, I will make the ganache and put the whole cake together. What do you think about putting some liquor in the ganache, and maybe even brushed on the cake layers lightly ? Such as chambourd, grand marnier, amaretto or frangelico ? BTW, thx for this inspiration, I have been so in love with the process of making this.
I’ve noticed that you called for All Purpose Flour in this cake, but you often use cake flour in other non-chocolate cakes.
Hi Surati, you can definitely try brushing these warm (or cooled) cakes with liquor. I haven’t tried adding any to the ganache, though. I don’t typically use cake flour in chocolate cakes since cocoa powder is already incredibly light. Doing so will create a flimsy cake without much structure.
I was very apprehensive about the chocolate seizing when I mixed the cocoa powder/hot water mixture with the melted chocolate mixture and my fears came true. I followed the recipe to a T and I used high quality chocolate (Perugina and Guittard). I googled how to save seized chocolate and thankfully I was able to save it by adding one tablespoon of boiling water to the mixture at a time until it was smooth enough to look like the one in the video. Hopefully, if anyone else has the same issue they can salvage their chocolate, rather than throw it way. The chocolate mousse tasted phenomenal in the end. Thanks!
Hi Sally!
I am in the middle of making this amazing looking cake for my brother’s birthday. I wanted to add sliced strawberries in between the layers with the mousse, would you recommend this? Or should I just save the berries for the top?
I am so excited to dig into this cake!
Thank you posting this delicious recipe!
Hi Lauren, for best taste/texture/presentation, I recommend only using berries on top. The mousse may liquefy a bit with sliced strawberries inside.
My sister and I made this recipe. It was amazing! Not to sweet and the cake was so moist! Thank you!
What can be the best substitute for sour cream? Thanks
Instead of sour cream, you can use plain yogurt. The cake won’t taste as rich, but it’s a fine substitute.
Baked this today for Mother’s Day (3 layers) and it was a huge hit! Followed all directions as written, and it turned out beautifully! DEFINITELY a chocolate lover’s DREAM!! ♥️♥️
Hi! Can you use two 9-inch cake pans instead? Like the triple chocolate cake recipe?
I wanted to make a mini Mother’s Day cake to drop off at my mother-in-law’s house, so I cut the entire recipe in half and split the batter evenly between two 6″ round pans. They baked beautifully in a 350 oven for 23 minutes. Thanks for the recipe!
Hi Sally! Thanks so much for the recipe! I have one question though. I made the mousse but find it’s a bit bitter for my liking and would like to know if there’s anything I can do to tone it down a bit or make it a bit sweeter and milder? Would I have to make a new batch of mousse or can I save it somehow? Thank you!
Hi Marv, you’re so welcome. You can fold in some confectioners’ sugar or granulated sugar to help sweeten it to your liking.
Hi Sally,
I want to make this cake this weekend for my parents. Is there any way I can make it a 2 layer cakes instead of 4?
Hi Kavya, you can squeeze this batter into 2 9-inch cake pans, but the cakes will be thick and you’ll have too much mousse filling. I recommend halving the mousse filling and ganache.
This was perfection. I’m just if the mouse can be used as frosting for cupcake with ganache drizzle?? On your chocolate cupcake recipe??
I can’t see why not!
Hi Sally. Cake was amazing. However, when I poured the hot water/cocoa mixture into melted chocolate, it seized. I had used 100% Ghirardelli Cacao Premium Baking chocolate and melted it in a glass bowl over (touching) boiling water. I rectified it by adding cream to choc mixture. But I’m confused because I thought that adding moisture to melted chocolate always caused seizing. As I said the whole cake ended up beautiful and delicious. But I’m perplexed why I’m the only one who had this problem!! Please advise. Thank you!!
Hi Mary, so glad you loved this chocolate mousse cake! Was the hot water/cocoa mixture still warm and the melted chocolate still fluid? The two should combine easily– you can see it in the video above. I wonder if it was the chocolate you used. I typically use Ghirardelli semi-sweet or Bakers semi-sweet baking chocolate bars.
I probably did not use semi sweet as I prefer using darker less sweet chocolates in general. It occurs to me that semi sweet have butterfat or some other dairy/milk product in them whereas the purer chocolate doesn’t, which would maybe explain why the cream helped fix it. I’ll try again.
What a cake! I don’t bake that often but wanted to make a special effort for my partner’s birthday as we are in lockdown. The recipe is so informative it was hard to go wrong and the cake turned out perfectly. The mousse balances out the richness of the cake really well. I found the ganache a bit rich but it definitely gave the appearance of the cake a finishing touch. I’m not sure what semisweet or pure chocolate means (maybe as I am in the UK?) so used half milk and half dark baking chocolate for the mousse and ganache and it was absolutely fine. I also only had two cake tins so baked in two batches.
Unbelievable cake. Made this for my husband’s birthday turned out phenomenal!