Chocolate Zucchini Cake

Super moist and indulgent chocolate zucchini cake is studded with chocolate chips and topped with chocolate fudge frosting. Made with three cups of shredded zucchini (you can’t taste it!), this is the most decadent way to eat your greens.

slice of chocolate zucchini cake on a black plate

Today, we have a triple dose of chocolate in the form of luxuriously rich chocolate zucchini cake. No, you can’t taste the zucchini. No, you can’t see the zucchini. Yes, it’s unbelievably delicious and I’m showing you exactly how to make it!

Chocolate Zucchini Cake Video Tutorial

Can you just look at how rich and moist this cake is? It tastes even better than it looks, I swear. The real secret behind it are the hidden vegetables inside. If you’re one who believes veggies should have nothing to do with dessert, keep an open mind. Carrot cake, anyone?!

slice of chocolate zucchini cake on a black plate with a fork

Why You’ll Love This Chocolate Zucchini Cake

  • Just as loved as my chocolate cake
  • Super moist and rich with mega chocolate flavor
  • Easy to make
  • Uses up summer zucchini
  • 3 cups of vegetables hiding inside– you don’t even taste it!
  • Covered in chocolate buttercream

Overview: Chocolate Zucchini Cake Ingredients

This decadent cake is made with fresh summer zucchini and pantry basics. Did you know that cocoa powder can dry out baked goods much more than flour? To compensate for this, we ensure there’s plenty of added moisture in the cake batter. Let’s review:

  • Flour: Sturdy all-purpose flour is the base of this cake recipe. Do not use cake flour– when combined with ultra-light cocoa powder, cake flour is too fine.
  • Unsweetened Natural Cocoa Powder: Cocoa powder takes the place of some flour. Just as in my regular chocolate cake recipe, make sure you’re using natural unsweetened cocoa powder instead of dutch-process cocoa powder. If you’re interested, see dutch-process vs natural cocoa powder for an in-depth explanation.
  • Baking Soda & Baking Powder: Use both baking soda and baking powder for lift.
  • Espresso Powder: Espresso powder accentuates the chocolate flavor. While optional, I highly recommend using it. The chocolate zucchini cake won’t taste like coffee. Rather, the espresso powder helps bring out the intense chocolate flavor.
  • Salt: Salt balances the flavor.
  • Oil: Oil adds moisture. You can try replacing *some* of the oil with unsweetened applesauce. I’ve done this with chocolate cakes and muffins and the result is wonderful, but I don’t recommend replacing all of it. Regardless of the zucchini inside, this isn’t health food, it’s dessert. Don’t make it something it’s not! 🙂
  • Sugar: We’ll use a combination of brown sugar and white granulated sugar. Brown sugar not only provides moisture, but flavor as well.
  • Eggs: 4 eggs bind everything together and add moisture. Remember room temperature is important.
  • Sour Cream: You can use sour cream or plain yogurt. Either add moisture.
  • Vanilla Extract: Pure vanilla extract adds flavor.
  • Zucchini: There are a whopping 3 cups of shredded zucchini in this recipe. Testing how much we can get away with… without actually tasting it! Zucchini is pure magic in cakes– nothing but flavorless moisture. Same goes with my zucchini bread, too!
  • Chocolate Chips: For mega chocolate flavor, add chocolate chips to the batter. They’re key to those melty pockets of chocolate in each slice. I use semi-sweet chocolate chips, but mini chocolate chips or even dark chocolate chips would pair wonderfully.

wet ingredients in a glass bowl and dry ingredients in a glass bowl

2 images of shredded zucchini on a white cutting board and chocolate cake batter in a glass bowl with a hand mixer

2 round cake pans filled with chocolate zucchini cake batter before baking

Overview: How to Make Chocolate Zucchini Cake

This chocolate zucchini cake comes together quickly and easily! Simply whisk the dry ingredients in one bowl and beat the wet ingredients together in another bowl. Combine the wet and dry ingredients, then add the chocolate chips. The cake batter will be slightly thick thanks to all of the zucchini! Divide the batter between two 9-inch cake pans or you can make a quarter sheet cake using a 9×13 inch cake pan. See my recipe notes for details.

  • Need cupcakes instead? This recipe yields about 24-30 cupcakes. See recipe note.

spreading chocolate fudge frosting onto layer of chocolate zucchini cake on a serving plate

Chocolate Frosting

We’re topping and filling this chocolate zucchini cake with smooth, silky, and creamy chocolate buttercream. We’re using my favorite chocolate buttercream recipe, but increasing the quantity. We do this for my regular chocolate cake, too. If you would rather top this cake with vanilla frosting, use the vanilla frosting included in my white cake recipe. Regardless of which you choose, you’ll have enough frosting to frost the entire layer cake AND a little leftover for some fun piping on top. Decorate however you’d like! I used Ateco #30 tip for the piping.

overhead image of chocolate zucchini cake with piped frosting decorations with a slice cut out

chocolate zucchini cake on a serving plate

Deep, dark, luxuriously rich, crazy moist, and weirdly loaded with vegetables that you absolutely can’t taste. After one bite you’ll be convinced this is the best way to eat your veggies! You’ll love my zucchini oatmeal chocolate chip cookies, too.

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slice of chocolate zucchini cake on a black plate with a fork

Chocolate Zucchini Cake

  • Author: Sally
  • Prep Time: 15 minutes
  • Cook Time: 30 minutes
  • Total Time: 3 hours, 30 minutes
  • Yield: serves 10-12
  • Category: Dessert
  • Method: Baking
  • Cuisine: American

Description

This super rich and moist chocolate zucchini cake is topped with milk chocolate fudge frosting- you won’t even taste the vegetables!


Ingredients

  • 2 cups (250g) all-purpose flour (spoon & leveled)
  • 3/4 cup (62g) unsweetened natural cocoa powder
  • 2 teaspoons baking soda
  • 1/2 teaspoon baking powder
  • 1 teaspoon espresso powder (optional)
  • 1/2 teaspoon salt
  • 1 cup (240ml) canola or vegetable oil
  • 1 cup (200g) granulated sugar
  • 3/4 cup (150g) packed light or dark brown sugar
  • 4 large eggs, at room temperature
  • 1/3 cup (80g) sour cream or plain yogurt, at room temperature
  • 2 teaspoons pure vanilla extract
  • 3 cups shredded zucchini (about 3 medium)*
  • 1 cup (180g) semi-sweet chocolate chips
  • chocolate frosting or vanilla frosting

Instructions

  1. Preheat oven to 350°F (177°C). Grease two 9×2 inch cake pans. (Make sure they’re at least 2 inches high, deep dish style.) Set aside.
  2. Make the cake: Whisk the flour, cocoa powder, baking soda, baking powder, espresso powder (if using), and salt together in a large bowl. In another large bowl using a handheld or stand mixer fitted with a paddle or whisk attachment, beat the oil, granulated sugar, brown sugar, eggs, sour cream, vanilla, and zucchini together until combined. Pour into dry ingredients and beat on medium speed until completely combined. Beat in the chocolate chips. Batter will be slightly thick.
  3. Pour batter evenly into cake pans. Bake for around 25-32 minutes or until the cakes are baked through. To test for doneness, insert a toothpick into the center of the cake. If it comes out clean, it is done. Allow cakes to cool completely in the pans set on a wire rack. The cakes must be completely cool before frosting and assembling.
  4. Assemble and frost: First, 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 or serving plate. Evenly cover the top with frosting. Top with 2nd layer and spread the remaining frosting all over the top and sides. Pipe any leftover frosting on top. (I used Ateco #30 tip.) Decorate with chocolate sprinkles or mini chocolate chips if desired. Slice and serve.
  5. Cover any leftover cake and store at room temperature for 2-3 days or in the refrigerator for up to 5 days.

Notes

  1. Make Ahead Instructions: Prepare cakes and frosting 1 day in advance. Keep cakes at room temperature, covered tightly. Refrigerate prepared frosting in an airtight container, then bring to room temperature when ready to use. Frosted or unfrosted cakes may be frozen up to 2 months, thaw overnight in the refrigerator and bring to room temperature, if desired, before serving.
  2. Special Tools (affiliate links): Box Grater, Glass Mixing Bowls, KitchenAid Stand Mixer, KitchenAid Hand Mixer, Round Cake Pan, Cupcake Liners, Cupcake Pan, #30 Ateco Closed Star Tip, and Disposable Icing Bags
  3. Blot the Zucchini: Give the shredded zucchini a very light blotting with a towel. Don’t squeeze too much moisture out, just a little blot before adding to the wet ingredients. I own and love this box grater— works quickly!
  4. 9×13 Cake: Interested in making a sheet cake instead? This batter will fit into a 9×13 pan. The bake time is long– at least 45 minutes to ensure the thick cake is baked through. Same oven temperature.
  5. Cupcakes: This recipe yields 24-30 cupcakes. Bake for 18-22 minutes or until a toothpick inserted in the center comes out *mostly* clean with no wet batter. Same oven temperature.

Keywords: chocolate zucchini cake

Also try these as cupcakes! Directions in the recipe notes.

chocolate zucchini cupcake topped with chocolate fudge frosting

249 Comments

  1. I’ve been hiding zucchini in chocolate cake since my boys, (now adults), were little.
    After trying many recipes, I thought I’d found the perfect one – the one that I’ve been using for years- until- on a whim- I found your recipe and OH MY GOODNESS!
    This cake is to die for- so chocolate -e and so moist – and amazing even without the frosting I didn’t have the chance to make.
    Thank you for sharing and for my new favorite chocolate zucchini cake recipe.

  2. So delicious! No one would ever know 3 cups of zucchini are in this cake! I needed a glass of milk to enjoy it fully, its very decadent. Thanks for sharing, I am saving the recipe!

  3. I made this recipe a few weeks ago and even with the “help” of my toddler, baking it in three 20cm pans in a slightly dodgy oven, and reducing the amount of sugar by about two-thirds, it was delish. I found letting it sit for a day got the balance just right between the super-sweet icing and my less sweet version of the cake. Am making again for my niece’s birthday tomorrow!

  4. I’ll definitely make this cake again. The cake has chocolatey depth, and I used Guittard extra dark chips (63%), so I opted for the vanilla frosting for balance. The Vanilla Frosting is great too. Got rave reviews from the four people I shared with.

    For your high altitude peeps: At a mile high, I did *almost* textbook adjustments—added 1/4 C. flour (2T. per cup) and cut the baking powder in half. Silly, but I couldn’t bring myself to halve the baking soda to such a small amount. Baked 24 cupcakes at 350 for 23 minutes. Cake was perfectly done, though domed a skosh too much (a little pointy) for proper results. I’m just happy they didn’t rise tall and then collapse into craters. Next time, I’ll cut the baking soda, too, in search of the perfect dome.

  5. Made this cake several times this Summer and it was a hit with everyone even our picky eaters! So moist and delicious chocolate cake heaven. Thank you

  6. Hi Sally, does this cake freeze well? Thanks, Ally

    1. Sure does! See instructions in notes.

  7. This is by far the BEST chocolate cake ever. Hands down. Everyone who has eaten it can’t believe it has zucchini in it. One week I made it 3 different times because it was loved that much. So simple to make and I didn’t even mention how unbelievably moist it is. It’s great without the frosting but why would you want to do that lol. Double the chocolaty deliciousness I say. I even turned it into cupcakes for easy serving. So glad you shared it. It’s one of my go too recipes.

  8. Hi Sally ,had never heard of a zucchini chocolate combo and I tried this out for a small baking competition and won the second place ! The cakes texture and taste was outstanding and would love to try out all your other recipes . Thank you so much

  9. I would rate it more than 5 if I could! I had RAVE reviews on the chocolates cupcakes I made!!! I need to make this a bunt cake for Christmas. What sort of baking adjustments should I make?
    As always, Sally, your recipes make me look good!
    Please get back to me ASAP, as I need to make this again on Tuesday.
    Thanks so much!

    1. Thanks Nancy! I haven’t tried this as a Bundt cake but readers have had success. Bake at 350 degrees F for well over the baking time the layers require. Keep your eye on it and use a toothpick to test for doneness.

  10. I just have say that this is the moist and by far the best chocolate cake I have ever made!!!!! Well done!

  11. Hi Sally! This cake tastes great, based on the scraps I had. I subbed half of the oil for applesauce and it worked brilliantly. For whatever reason, I wasn’t expecting it to be as deeply moist as it was on the outside, which made decorating it a bit of a challenge. Could be I just didn’t use enough frosting (I used the swiss meringue buttercream on it). Thanks for another good recipe.

  12. This is my favorite recipe of all time. And I love that my kids request it for their birthdays!

  13. Catherine Sullivan says:

    All I had at home was Dutch processed Special Dark cocoa powder. I added 1 tablespoon white vinegar for an acid to react to the baking soda. It turned out amazing!

  14. I replaced the zucchini with steamed broccoli wizzed in the food processor. It was AMAZING and my green phobic 4 year old had no idea he had just consumed his nemesis

  15. Hi Sally! Could I put fresh strawberries sliced up in between the layers to add freshness or would that just be too much moisture?

    1. Hi Katie, It’s a very moist cake but you can add berries between the layers if you wish.

  16. Could you replace the canola/vegetable oil with virgin olive oil?

    1. I recommend 1 cup of melted coconut oil as a substitute for the vegetable oil.

  17. Hi! Has anyone tried this with a gluten free flour, specifically almond or coconut flour? Thanks in advance!

  18. What can I use instead of zucchini? I only have one and I want to make it today, please help!

    1. Shredded apple or carrot works too!

  19. Hi Sally! Your cake certainly lives up to ALL its claims – super moist, delicious, dreamy!!! I used what I had on hand – subbed light brown sugar for the white sugar, plain drained yogurt for the sour cream, chopped up 72 % cacao dark chocolate bar for the chocolate chips, packet of finely crushed instant Sanka for the espresso powder, used unblotted grated zucchini & *added* at least 2/3 cup of hot strong brewed coffee for extra moisture. Batter was thinner at that point but baked up beautifully in no time flat with an unbeatable texture. Only thing I’d do differently would be to melt the chocolate chips into the hot coffee before mixing in to really intensify the chocolate flavor throughout this champion of cakes! I used a swiss meringue buttercream for frosting, then drizzled a a stream of thin ganache on top…Thank you so much for this masterpiece of a cake!

  20. Great recipe! My family and neighbors loved it. Got more than 30 cupcakes out of it and used Ganache on top instead of buttercream due to transportation issues. Tasted great on day 2 as well. Thanks for sharing.

  21. Hi Sally, thank you for sharing your amazing recipes. I have tried so many chocolate zucchini cakes/muffin recipes all somewhat dry. Yours is the best according to my husband and granddaughter . I made the cake and muffins or my sons bday (43) and will deliver them curb side tomorrow. Thanks again be well and stay safe!

  22. This is our family’s favorite chocolate cake recipe and we make it every year at least once. I was wondering if I could halve the recipe to make a single layer cake? The heart wants the double layer but the jeans are begging for a single layer during quarantine. Haha! Love your site and all the hard work you put into your recipes.

    1. I’m so happy your family enjoys it, Amy! Yes you can cut it in half 🙂

  23. Allison W. says:

    Thank you, thank you, thank you! While I’m a pretty fair baker, I’m not typically good at making chocolate cake. In my opinion there is nothing worse than dry chocolate cake. I actually halved this recipe and put it into 2smaller, round pyrex glass bowls. My husband hates cake and so I usually make half the amount so I don’t eat the whole thing! I then have a mini double layer cake just for me. Well, I was letting it cool and hubby told me how good it smelled. He actually asked for a “taste”. I hadn’t frosted it yet but told him to take a bite at his own risk, not letting him know about the zucchini. He ate the whole stinking small cake leaving me with only a 1/2 of a 1/2! Honestly, in my opinion it doesn’t even need frosting! I did put a few extra chocolate chips in the batter because, well-it was my cake after all! Yum! This is a definite keeper. You are a genius.

  24. Thanks for cross-referencing recipes since I started out looking at zucchini cookies and the chocolate zucchini cake sounded more appealing. I also made half the recipe and not planning to frost. I know the sugar and fats make these recipes so much tastier, though I prefer to use a little less so will see how it turns out. Hopefully the ratio of dry and wet ingredients didn’t change too much when I made these small adjustments.

  25. Hi Sally,

    Can I use Chocolate Crean Cheese Frosting instead?

    1. Sure can!

  26. Hi Sally, I love this recipe and have made it before with lots of success however, during a pandemic a 8″ double layer cake is a lot for 2 people. If I cut the recipe in half can I get away with a 2 or 3 layer 6″ cake? Thanks! Hope you and your family are doing well.

    1. Stephanie @ Sally's Baking Addiction says:

      Hi Kellie, You can cut the recipe in half and just make a single layer 8 or 9 inch cake. If you wish to change the pan size you can use the post on Cake Pan Sizes and Conversions to calculate how much batter to use.

  27. Doris & Alan says:

    OMG… We’re in chocolate heaven. This is just the most delicious chocolate cake we’ve ever made. (Both my husband and I bake). Didn’t even frost it…it is truly so moist that you don’t want anything to take from that moistened bite. And we are chocolate fanatics. Sharing the recipe all over the place..

  28. Deb Gundersen says:

    The cocoa I have in the house is Hershey’s Special Dark. It says it is a combination of natural and Dutch cocoa. Can I use it in this cake recipe? Also, will the recipe work with gluten free flour.

    1. Hershey’s Special Dark works in this recipe– I’ve used it before here! I haven’t tested the recipe with gluten free flour, but let me know how it goes!

  29. This was a yummy cake and no one detected the zucchini.. moist and chocolate lovers like me loved it.. my boys (men) loved it..my grandkids thought it was tasty..next trying out your naked cake for my birthday

  30. Just made your chocolate zucchini cake and it looks delicious. What garnered my attention to your recipe was the 3 cups of zucchini. The last recipe I made only took 2 cups of zucchini. Can’t wait to taste it. I have also made your strawberry and the lemon blueberry cakes with great success. My daughter saw the strawberry cake I made for a friend and decided upon the spot that would be her BD cake this year. She has previously for years requested a coconut cake from an old recipe book from my previous work. I usually go to your site before making any new cake and am never disappointed. Thanks for all your wonderful recipes.

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