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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 these veggies should only be in feta herb zucchini bake, and 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: Remember my lesson on baking soda vs baking powder? We use both here 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 and zucchini muffins, 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. Whichever kind of chocolate chips you enjoy in your chocolate chip cookies, you’ll enjoy here, too.
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 1012 1x
  • 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

Scale
  • 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

Reader Questions and Reviews

  1. Beautiful rich chocolate cake that doesn’t taste like zucchini in it at all after it is set aside for a day. I switched oil for butter, sour cream for yoghurt and only 3 eggs with a little bit of full cream milk to add the moisture missing from that extra egg. My husband didn’t even notice I added zucchini to the cake. He usually tells me if I changed the recipe or something was different. I am super impressed and will make this cake as a regular for the family now.

  2. Fantastic! This was a superb recipe. If anyone is wondering, yes, you can use those really BIG zucchini’s from the garden. I used my processor to grate them and squeezed out the moisture using a jelly bag. Works great!
    This is my second cake in 2 days. One for our household, and another for the neighbour. Will be making another for work. Very moist, delicious and not too sweet.
    Also made in a bundt pan and poured a chocolate ganache over top once it cooled. Thanks for a really great recipe!

  3. Made this with a gluten-free flour blend and lactose free plain Greek yogurt. Had to increase the baking time to 40-45 mins but turned out terrific! Can’t tell it’s even modified. Paired it with the vanilla frosting made with lactose free butter and oat milk. This recipe is a keeper for us!

    1. This recipe is delicious as is, no need for frosting. I made it in a Bundt pan and it took about 45 minutes to bake.

    2. When using the gluten free blend did you use the exact amount of regular flour as the recipe calls for? Would love to make this. Having celiacs I haven’t really found a tasty recipe yet. With GF blend and veggies, I’ll get my chocolate fix and veggies al in one!
      Thank you

    3. When using the gluten free blend did you use the exact amount of regular flour as the recipes calls for?? Would love to make this. Having celiac I haven’t found a tasty recipe yet. With GF blend & veggies, I’ll get my chocolate fix plus veggies all in one.
      Thank you

      1. I used gluten free as well. My daughters friend has celiacs. Used the same amount of coconut and almonds flour mixed. Moist and delicious!

  4. This cake is a revelation! Moist to the point of ecstasy, deeply flavorful, sturdy but yielding it plays on the tongue like few cakes I’ve ever eaten. I will make this again and again. I’m going to make it for desert when company comes for dinner. Thank you!

  5. I made this recipe and it really is 4.5 stars, I rate recipes on ease of making, quality of recipe and likeably of taste testers. I changed/used the following ingredients: all purpose flour to King Arthur cake flour (2c + to equal 250g), I used vegetable oil (no canola oil), I switched out granulated sugar for 5/8 c maple syrup, I used plain yogurt. I used espresso powder so it may keep you awake at nite. Recipe yielded 24 cupcakes and a mini cake. I haven’t frosted them yet, but they taste great and I will make again!

  6. My son isn’t a huge fan of chocolate. Will the cocoa powder be enough for a chocolatey flavour or is adding the chocolate chips a must?!

    1. Hi Marina, you can leave out the chocolate chips in this chocolate zucchini cake!

      1. Hi Emilia, We don’t see why not. Bake time will be shorter with thinner layers, so keep an eye on them in the oven.

    1. Hi Eva, you can replace the vegetable/canola oil with olive oil, but since it’s not as neutral tasting, the end flavor of the cake might change a bit.

  7. I replaced the vegetable oil with coconut oil and it was a delightful additive of flavor!

  8. I would like to make this for my son’s birthday (tomorrow). He has type 1 diabetes. Do you know how many carbs are in 100g of this cake? I need to know how much insulin to give him…

    1. Hi Kate, we don’t usually include nutrition information as it can vary between different brands of the same ingredients. Plus, many recipes have ingredient substitutions or optional ingredients listed. However, there are many handy online calculators where you can plug in and customize your exact ingredients/brands. Readers have found this one especially helpful if you’d like to try it out: https://www.verywellfit.com/recipe-nutrition-analyzer-4157076

  9. I have group of friends and I made this cake for one of them because he does not eat vegetables. I did it as a gag. The cake was absolutely sensational . Now I’m ask to make it at every time we get together. It’s great. One question. I just recently read your article about dutch process cocoa and I saw where you did not recommend it for this cake. I have probably made this cake 10 times (in a 9×13 pan), using Hershey’s Special Dark and it has come out wonderful each and everytime. Any thoughts on why? I love your recipes. Ed P

    1. Hi Ed, We are so happy that this cake was a hit with your friends! Hershey’s Special Dark cocoa is actually a mix of natural and Dutched cocoas. We’ve used it before in this recipe and it’s wonderful!

    1. Hi Jen! Yes, you can use frozen zucchini. Thaw, then squeeze out most of the excess liquid.

  10. Rating based on following the recipe with no subs. Excellent rich chocolate cake for real chocolate lovers. Nice depth of flavour and its very moist and has a great texture. Will make again for sure! I paired it with ermine icing for a lower sugar option for birthday cupcakes.

  11. My daughter made this at school and it was delicious. Would it be ok to freeze as its a lot of cake for just one person and alot went to waste, no one else in the house will try it but I’d like her to make me another one!?

    1. Hi Denise, absolutely. See recipe notes for freezing instructions.

  12. Hi
    Thank so much. I took your recipe and fiddled a little (inline with science-ish!) to create a cupcake for a London UK kids birthday party, replacing sugar with xylitol (from Birch trees, not corn) and half the oil with organic butter and finely shredded carrots and courgettes. I make a frosting using xylitol melted into 70% chocolate and low fat mascarpone). Beautiful recipe and the kids loved it. Thank you xxx

  13. I would like to make this for a friend tonight, but I only have 1.5 zucchinis to work with. Should I add a little apple sauce to sub, for moisture? I do have summer squash, but I’ve never tried that in baked things before. Thoughts? TIA!

    1. Hi Lola! Just seeing your question now – summer squash would have worked to make up the difference! Hope you loved the cake.

  14. Hi there, could I use coconut yogurt to make it dairy free? Would the recipe need changing?

    1. Hi Annalise! We haven’t tested a dairy free version of this cake but let us know if you do!

  15. I completely forget to dab out some of the moisture of the zucchini, so I was a little scared of how the turn out would be. But it was so, so moist and decadent. Added in crushed up Oreo pieces and made Sally’s chocolate cream cheese frosting. Absolutely amazing and will be making again and again and again. Husband’s work also raved about the cake! 🙂 Thank you for always coming through with the BEST recipes. Can never go wrong when finding a recipe here.

  16. This is a wonderful recipe and always a crowd pleaser. I make this cake for birthdays and it is always a hit!

  17. I made this for my son’s birthday today and got many compliments! No one knew that there was any zucchini in it; some even asked for seconds! Reduced the amount of brown sugar in the cake as I planned to put whipped buttercream frosting with crushed Oreos between layers and chocolate frosting on top with some Oreos standing up.

  18. I doubled this recipe and made it for the teachers where I work. It was very much appreciated. Funnily enough I was standing next to a PE teacher during a class and he mentioned about how fussy kids are with their eating. Apparently as soon as he heard it was made with zucchini, he couldn’t finish his piece of cake.

  19. This recipe was so good!

    I thawed out what was supposed to be 3 cups of shredded zucchini but it only came out to 2. I added another cup of milk and it worked great!

    I also topped it with a chocolate ganache made with 1/2 cup whole milk, 4 tbsp of butter, and 9 oz chocolate chips. I made it as if it was made with heavy cream.

    Finally, I made mine as a bundt cake. I ended up baking it for about 40-45 minutes.

  20. Perfect chocolate cake ! This now my go to chocolate cake for any reason and in any form. Thanks so much !

  21. Hi! I’m interested in making this cake but a question before I do – I need to make a 3-layer cake to be decorated with fondant. Will this cake hold the weight of the fondant? Is it sturdy enough? Thank you!

  22. Just wondering why you use oil instead of butter? I am making this cake at the weekend.

    1. Hi Fiona! Oil adds unparalleled moisture in this zucchini cake – we don’t recommend butter here.

  23. I don’t think I’ve ever posted a recipe review but this is hands down the best chocolate cake I’ve ever made. It’s not overly sweet and I think of it as a dark chocolate cake in flavor. Loved the soft texture of both the cake and the frosting!

  24. Planning to make this for Easter with Bob’s Red Mill 1 to 1 substitute flour to accommodate a wheat allergy in the family. I’ve subbed that flour in for many cakes over the past two years, and no one can tell the difference! Question: Should I frost it with your chocolate cream cheese frosting or your regular cream cheese frosting? Wasn’t sure if it could get too chocolatey… Is that possible? 🙂

  25. I couldn’t find it, perhaps I’ve missed it, but just to be sure: when coverting this recipe to cupcakes, you should fill the cupcakes for 2/3 full?

    1. Hi Kate, correct! We fill the liners about 2/3 of the way full.

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