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.

More Chocolate Recipes

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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 (63g) 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

444 Comments

  1. Smoke Cohea says:

    Hi Sally, My 75 year old dad just loves your site! On this recent visit we made your chocolates zucchini cake, oatmeal chocolate chip cookies, chewy chocolate chip cookies, and your deep dish apple pie. All are amazing! We love all your pictures and your detailed recipes.
    We are excited for you about the new addition to your family and wish you all the best!
    Christine and Smoke

    1. Thank you so much for reporting back about all the recipes! I appreciate it so much. Thank you for the congrats, too!

  2. Can you use instant coffee powder instead of espresso powder like in the double chocolate zucchini bread? It called for 2x as much instant coffee powder as espresso powder in the bread, and I was curious if it would be the same ratio in the cake??
    PS: I have made 4 batches of double chocolate zucchini bread and 4 batches of your award winning zucchini bread, and we can’t stay out of them! I had to stick half of the loaves in the freezer to keep us from eating them

    1. Sure can! I’d use 1 and 1/2 teaspoons (or up to 2 tsp) instant coffee in this cake.

      1. Great! Can’t wait to try it!

  3. Tammy Sepulveda says:

    In this double chocolate zucchini cake… is the chocolate that is piped on top the same as the ftosting? In the picture it looks a different color (darker).

    1. Yep, it’s the same. I didn’t make a separate frosting for that part! Must be the lighting.

  4. Jenny Hughes says:

    I am wondering if this fluffy brown sugar icing would be good on this cake instead of chocolate frosting. My husband loves fluffy brown sugar icing and I want to make this cake for his birthday.
    http://www.iwashyoudry.com/fluffy-brown-sugar-icing/?m

  5. Hi Sally, do you know how many slices I can get from this cake? (How many people should this serve?) Would it work if I made 50 percent extra amount of everything and make 3 layers? Thanks!

    1. Hi Zuzana! Cake serves 10-12. You can try to 1.5x the recipe. I don’t see an issue from that, though I’ve never tried it before.

  6. Hi Shelley! Calorie counting calculators online can often be inaccurate (different brands/products/etc) and I would hate to publish wrong information on my website. Sometimes I share an estimate, but that’s rare– feel free to calculate at your own discretion for the chocolate zucchini bread.

  7. Sally, I made this cake and oh my gosh it is amazing. I froze part of it with icing on it and it did great. I took it to my Sissy and first bite her eyes rolled back in her head. Her son is getting married next year and she told me THIS IS IT! We are on the search for cakes to make for the rehearsal dinner and she wants me to make them for her. She said This is the one for the Grooms Cake! If her son falls for it the way she did. But she has to stay out of the rest of it for him to try it. haha. I have a feeling I will be making at least one or two more of your cakes for the rest of the dinner but we are still in the deciding fase. You have made me such a Hero! I have found the extra ingredient in everything is The Love! Or least she says so. Oh i made your double choc zucchini bread and regular zucchini bread in one day (double batches) also. Oh my goodness they are so amazing. She says the double choc. is Nervana! They freeze well so that makes it even better. Thanks! I didnt use coffee in mine as we hate coffee and it was still great.

  8. I am now making another batch. Second one in 2 weeks. Really great cake! Everyone I have a piece to loved it!  

  9. Hi,this cake seems delicious.love the pics.I had a few doubts,it would be great if you could help…please….really want to eat this cake

    1.Will this cake taste yummy and chocolaty without the icing?
    2.Can we reduce the sugar in the cake,as my family do not like very sweet cakes?
    3.Can this recipe be halved?
    4.Can I use 4 medium eggs instead of 4 large ones or do I use 5 medium eggs?

    Thanks a lot in advance for your help.

    1. Here to help! 1) I’m sure it would, yes. 2) You can try, though the texture may be compromised. 3) I can’t see why not! 4) I’d use 5 medium eggs.

      1. Thank you for your reply,will definitely bake this and let you know.

  10. Diana S Buswell says:

    Hi There, cannot wait to make this cake. I have a question, should I express the moisture out of the zucchini? , Or leave it as is shredded. Thanks in advance.

    1. See my recipe note– enjoy!

  11. I was in a baking mood this weekend and saw this on my facebook feed and thought I had to try it. Since there is only two of us I halved the recioe and cooked in two 6 inch tins. I used a sour cream chocolate crosting with melted milk and dark chocolate. The cake was very moist and my husband loved it. You can’t taste the zucchini! Thanks Sally again for a great recipe. Good luck with your new addition.

    1. That frosting sounds amazing with this cake! And thank you so much 🙂

  12. I just baked this cake for my 25th Wedding Anniversary, tomorrow. Is it absolutely necessary to let the layers cool completely in the pans? This is a first for me. Thanks!

    1. Yep, otherwise they may stick.

  13. We have an overload of zucchini in our garden this year and it just so happened to be my dad’s birthday yesterday. He’s a huge chocolate fan so it only seemed right to make a chocolate zucchini cake with chocolate icing. And boy! Are we ever glad we chose your recipe! It was a huge success in our family and everyone went crazy for the moist chocolate cake… Let’s just say there is no more cake left today. Next up, we’re going to try your double chocolate zucchini bread.
    Thanks for the wonderful recipe! It’s a keeper for sure 🙂

    1. You are welcome, Mika! So happy your family enjoyed it and happy birthday to your dad! 🙂

  14. Wilma Haumesser says:

    LOVE LOVE LOVE this recipe!❤️❤️❤️

  15. Can i subtitute natural cocoa with dutch cocoa and remove the baking soda and replace them with twice amount baking powder? 

    1. I don’t suggest it.

  16. I found this recipe/site while looking for something to do with the zucchini from the garden. This sounds and look delicious. I was wondering if this would bake correctly in loaf pans–maybe 2 or 3.

    1. Sure would! Fill them up halfway. I’m unsure how long they’ll take.

      1. I will let you know–thanks for getting back to me so quickly!!

  17. Hi! I want to bake a chocolate cake this weekend, but can’t decide between this chocolate zucchini recipe or your triple chocolate layer cake recipe. Could you tell me how the results of each one will differ in terms of taste/texture etc? Thanks!

    1. They are both rich and moist and you can’t go wrong either way!! The chocolate zucchini cake has chocolate chips inside the batter so if you want more texture try this one.

  18. I made this for my brother in laws birthday last week but didn’t tell anyone there was zucchini in it. I received so many compliments, including one from my dad saying I’d “outdone myself this time, best cake ever”. He absolutely detests zucchini with a passion! His face when I told him was priceless! 🙂

  19. Could this be baked in a bundt pan? If so, what temperature and time do you suggest?

    1. Sure can! Same oven temp, but I’m unsure of the bake time.

  20. OMG! i have watched the video of the chocolate zucchini cake like 50 time and i keep watching. Almost eating the cake as i am watching…actually drooling right now. I am in the office and can’t wait to go home and try it out. Its absolutely gorgeous….

    1. Thanks, Abi! Hope you can bake it this weekend and let me know how you like it!

  21. Hi….I want to make the Chocolate Zucchini Cake & I want to use espresso powder…. I have looked in the grocery stores in the coffee area but I don’t see it.
    What kind of a container does it come in?

    Also you suggest chocolate fudge frosting or vanilla frosting…so I clicked on it and it brought me to a page that had Milk chocolate frosting….where do I find the chocolate fudge frosting recipe?

    Please reply. Thanks.

    1. Hi Patricia, The espresso powder usually comes in a can or jar and in my local stores is on the shelf next to the instant coffees. The chocolate fudge frosting IS the milk chocolate frosting – they are one in the same! 🙂

  22. I was ecstatic finding your recipe. I searched all over for my late Mum’s recipe but couldn’the find it. It is cooling on the counter and I am anxious to see how close it is to Mum’s!!

  23. So this cake is amazing! All I had was Hershey’s dark cocoa powder so I used that in the cake and frosting and it was amazing. So moist and rich. Thank you for the recipe! This is the exact kind of texture and moistness I want in my chocolate cake and sometimes a homemade chocolate cake doesn’t always result in it… at least for me. But this one does not disappoint!

  24. Yasmine Maggs says:

    Hey Sally. Made your Chocolate Courgette Cake yesterday and it was amazing! Probably the best chocolate cake I’ve ever tasted. Thank you so much. I love your recipes & website. Lots of love from the UK. x

  25. I’ve tried a lot of zucchini chocolate cakes over the years, but this one is my favourite by far…just awesome! I made it in a 9×13 pan, and the only change I made was to use 1/2 cup milk choc chips and 1/2 cup semi.

  26. Hi Sally  
    Would you recommend the chocolate zucchini or the super moist chocolate cupcakes for a chocolate lovers birthday ? 
    I’m torn between the two brand new chocolate recipes! 
    Thanks! 

    1. I suggest the super moist cupcakes 🙂

  27. Just made this cake with the chocolate frosting. I made it exactly as shown but did not add the espresso. It is absolutely amazing and super moist.

    1. Hi Shelley, I’m so happy you liked it! 🙂

  28. This was a really great, moist cake with a great texture. I followed the recipe but omitted the chocolate chips and the espresso powder and also baked it in a half sheet pan (18×13) for 25 min and it came out great–similar to a Texas sheet cake and perfect for a large gathering! Thanks for the recipe…next time I think I will add a t. of cinnamon to the mix:)

    1. Happy to hear you made it work for you! I love chocolate and cinnamon – let me know how it turns out!

  29. Austria Azaceta says:

    Hi Sally!
    So I made this cake last week (frosting & all) for my sister’s birthday & just had to let you know how incredible it was.  So so so so so goooooood!!!  The espresso powder is EVERYTHING!  It was super moist fluffy cake & such amazing chocolate flavor without being super sweet.  I even got yelled at by my brother in law for (& I quote) “making such delicious cake”. 🙂
    Thank You!!

  30. Hi Sally!

    My 9″ round cake pans are only 1.5″ high – what would happen if I used these instead of a 2″ deep pan?

    Thanks!

    1. The cakes would overflow 🙁

      1. Thanks Sally!  I ended up finding a 2″ deep cake pan and used it to bake the cakes.  They turned out yummy but it didn’t rise much at all! Each layer was only about an inch tall. Your pics look like they rose higher. Any clue as to what I might have done wrong?

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