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

254 Comments

  1. Can you make this with frozen zucchini? Thanks!

    1. Trina @ Sally's Baking Addiction says:

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

  2. Louise McDonald says:

    This cake is delicious, can’t tell there’s any zucchini in it. Left out the chocolate chips and baked in a bundt pan until tested done , approx 55 minutes . From past experience, the chips will drop to the bottom and keep the cake from releasing from the pan. Put a vanilla glaze on it. Family loved it.Will definitely make again.

    1. Louise…I’ve had this problem with cc’s as well when making chocolate pound cake, but chopping the chips (if they’re unusually large) and/or tossing them with some of the flour has definitely helped, as well as coating the bottom of the pan well with oil and powdered sugar.

  3. Omg! For years people have loved my moms hand me down moist chocolate cake recipe! But this cake surpasses moms cake by far! This is the most delicious,moist, chocolate decadent cake I have ever made ! My husband said “ I hate to say it but this is better than your moms!” Lolol Thank you so much for sharing! By the way….. I added a few white chocolate chips along with the chocolate chips and some oven roasted FISHER pecans to mine! What a treat!

    1. Donna Stuebing says:

      I have made this cake 3 times in the last 2 months. My husband ate one by himself and he is diabetic! It is so good. I did use yogurt because im not a fan of sour cream. The squash has so mucn moisture, it cant help but be delicious. I went by the recipe and see no need for any changes, it is that good. It is a little time consuming because it has a lot of ingredients and grating the squash takes the most time, but it is so worth it. This is the first time i have taken the time to write a review on anything.

  4. Patricia McKenzie says:

    Can you use a food processer to grate the zucchini or does it have to be a box grater?

    1. Lexi @ Sally's Baking Addiction says:

      Hi Patricia, you can use the grating setting on your food processor, just be sure not to over pulse and make the zucchini too wet / mushy.

  5. Hi! I was just wondering, on the zucchini, do you usually peel it or deseed it before shredding it? Or just wash it and use the whole thing, seeds and all? Thanks for all the amazing recipes! I have used several of them and love them all!

    1. Trina @ Sally's Baking Addiction says:

      Hi Brandy! We just wash the zucchini and shred it whole. Enjoy!

  6. I have made this cake many, many times. I am still befuddled by the measurement conversion of grams vs cups. The flour and cocoa work out pretty good, but the sugar conversion is way off. You, and every other source indicate that one cup of sugar is 200gms. I have measured and weighed on two different scales and had a friend do the same. We both consistently get 140 grams. That is a big difference and would significantly change the taste. I so prefer using metric measurements but use Imperial for this reason. I don’t expect you to solve this issue, but has anyone else ever commented on this?

    1. Hi Kenna, just to let you know, I made the recipe following metric measurements for everything, including 200g for sugar. It was spot-on perfect. Thank you Sally for providing both cups and metric measurements!!

      1. Ooh, but there’s no metric measurement given for zucchini!
        Would 350g (by volume not weight) be enough?

  7. Nikkie Krebs says:

    I always do mine in the blender it is amazing just make sure you put in a cheese cloth and squeeze juices out but it works great

  8. Loraine Parry says:

    Before I make the chocolate zucchini cake, I’m wondering if there is a substitute flour to use for someone with a gluten intolerance

  9. The recipe was very well written with the examples, suggestions and photos. I was surprised to get a request from my niece for a chocolate zucchini cake, and found yours. It just so happened that a friend had given me a big zucchini from her garden too. It had been several years since I had baked a layer cake, and it came out perfect. The only thing I added was a teaspoon of the instant espresso powder to the chocolate buttercream frosting. Everyone loved it….think I’ll have a slice with my morning coffee. It was a hit, and oh so beautiful. It was a perfect ending to the first meal we’ve shared in 16 months because of the pandemic. So this will be quite memorable. Thank you.

  10. This is definitely the best chocolate cake ever! It is so very moist and full of flavor! Every year our garden is overflowing with zucchini , so I make good use of it by making this cake. I grind the zucchini in the food processor to freeze in 2 cup packages so I can make it throughout the year. I have your recipe from 2009 that has different amounts of the ingredients from this recipe, and have been making it since. The only substitutions I make are that I use dark chocolate chips in the cake and cover it with a dark chocolate Ganache, then sprinkle with ground Oreo cookies on top. I have made it many times, and everyone just loves it and wants the recipe.

  11. I was just given two cupcakes from this recipe, amazing! Now my husband is asking for this cake over the weekend, so now I need to get some espresso powder and zucchinis

  12. This was a truly wonderful cake. I also used the chocolate buttercream frosting recipe from this site. The only thing I’d change in the cake is to leave out the chocolate chips in the batter. They solidified back up after leaving it in the fridge and you bit into the chips while eating – I’d personally prefer a smooth cake but that’s just me. Will definitely use this recipe for all future chocolate cakes. Thanks so much ❤️

  13. Delicious! I halved this recipe and made 14 mini-bundt cakes (using cupcake instructions). Drizzled with a simple peanut butter glaze and OH MY! A big hit! Thanks for another great one!

  14. If you wet a 2″ wide length of old toweling and wrap it around the pan before baking you will have a level cake and don’t have to cut the you off. Wilton has professional wraps you can buy.

  15. Lynne Smith says:

    I made this cake for my birthday. MMM MMM the absolute best. I spread strawberry jam between the layers at the request of my husband. Only iced the top and front sides as I ran out of icing. Still so good. Making it again today. This recipe is a definite keeper.

  16. I was told by a fellow baker (er, baxter) that cocoa powder need to be “activated” by heating it in liquid prior to mixing it with the other ingredients. Is there any truth to this? Regardless I have zucchini to use up and I am SO trying this recipe tomorrow!

    1. Trina @ Sally's Baking Addiction says:

      Hi Terry! Hot liquid enhances the cocoa powder’s flavor and encourages it to bloom and dissolve appropriately but it isn’t always necessary. It mostly depends on the proportion of dry ingredients. No need in this recipe with the added moisture from the zucchini. Hope you enjoy this cake – let us know how it goes!

      1. Well I baked the cake Saturday and frosted it yesterday…had to increase the frosting by half in order to cover the whole cake (I didn’t try to decorate). The cake gets props for moistness, a softer crumb and a taller rise than I typically get using whole-grain flour (1:1 hard white:soft white for all-purpose flour), and the chocolate chips definitely make their presence known; BUT the cake itself doesn’t taste very chocolatey. My husband and I both tried a slice last night and found it very good overall. I’ll be making this again when it’s time for more cake and I have zucchini to use up, but I may either add more cocoa to the batter or try heating it first.

  17. Can i use greek yogurt instead?

    1. Lexi @ Sally's Baking Addiction says:

      Hi Katrina, plain Greek yogurt works. Enjoy!

  18. I don’t know why, but this smelled and tasted like zuchinni. It went to waste. I didn’t measure cup wise once grated, I just had 3 medium zuchinnis. So I guess I shouldve measured. I would make this again without the zuchinni..

  19. Hi, can you use coconut oil or avocado oil instead of Canola oil?

    1. Trina @ Sally's Baking Addiction says:

      Hi Kara! Coconut oil should be a good sub, we haven’t tested avocado oil. Let us know how it goes!

  20. Have made this several times. It’s glorious and everyone loves it! I was wondering if a GF 1-1 version would turn out well?

    1. Trina @ Sally's Baking Addiction says:

      We haven’t tested it, but let us know if you do! Other readers have reported success with similar swaps.

    2. I just made one yesterday with a GF flour blend. Turned out terrific!

  21. Omg this cake is delicious!! Great recipe. I just altered to make it dairy free (son has allergies to milk). So added soya yogurt. And a vegan butter for the frosting. Thank you for recipes I will be baking more zucchini, I have excess from garden great way to use the larger courgettes.

  22. Carolyn Meyer says:

    You have 2 cups of flour and 200 grams weight. That was less than 2 cups. I went with the 200 grams since the cocoa weighed more than what was in 3/4 cup. Could you clarify the weight please of the flour and cocoa?

    1. Hi Carolyn, 2 cups of spooned and leveled flour is 250g. That is what the recipe calls for.

  23. Excellent! Super moist and I added chocolate chips on the top (as well as in the batter)

  24. This was so tasty and moist. I have made a couple double batches and the reviews of the taste testers is OMG.

    I added walnuts to the batch I made cupcakes with. So good.

  25. Really yumm recipe! moist and soft. I used only 1 cup of xylitol instead of sugar and it turned out perfect. However I do feel a slight after taste of the bicarb on my tongue, how do I avoid that?

  26. I made this cake for my brother’s birthday a few weeks ago. Everyone loved it! One of the comments made was “Ah! I didn’t know I was eating it so fast, it’s so good.” I added some coffee to the batter in place of the optional expresso powder and used a chocolate ermine frosting instead of the posted (probably) buttercream.

  27. Loved this cake and a way to use up my zucchini! I have my own favorite frosting recipe so used that ! My daughter thinks it rates high up there on her list. I have tried many recipes on this site. All good!

  28. Do you find if baked in a 9×13 pan, the edges get dry? I LOVE this recipe but have only used 2 9×9 but am interested in making a sheet cake.

    1. Lexi @ Sally's Baking Addiction says:

      Hi Angela, we don’t find that the edges get overly dry when baking in a 9×13, but if you find that happening with yours, feel free to tent the edges of the cake pan with foil to prevent them from over-browning.

  29. First time I’ve made chocolate-zucchini cake in many years, and this is a real winner. The recipe adapted very well to substituting cinnamon-flavored storebought applesauce for half the oil, whole wheat pastry flour for AP flour, milk chocolate chips for the semi-sweet – and not blotting the zucchini (and using just a little extra). It’s such a treat, even without the frosting. Thanks!

  30. Great moisture and flavour, I think it tastes better the day after.!!
    I substituted mayo as I ran out of yogourt. I will definatly be making another one to freeze.

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