Super moist and indulgent chocolate zucchini cake is studded with chocolate chips and topped with chocolate fudge frosting. Made with 3 cups of shredded zucchini (you can’t taste it!), this is the most decadent way to eat your greens.
I originally published this recipe in 2017 and have since added new photos, a video tutorial, and additional success tips.
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! Zucchini recipes have never been more decadent than this one. 🙂
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 is the hidden vegetable inside. If you’re one who believes these veggies should only be in zucchini casserole, zucchini fritters, or zucchini biscuits and have nothing to do with dessert, keep an open mind. Carrot cake, anyone?!
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
- A delicious way to use up a bumper crop of summer zucchini
- 3 cups of vegetables hiding inside—and you don’t even taste it
- Covered in fudge-like chocolate buttercream
One reader, Stacie, commented: “Delicious chocolate cake! No evidence of three cups of zucchini in there! So good!!! ★★★★★“
One reader, Emily, commented: “This was amazing! Probably the best chocolate cake we’ve ever had—so moist! And no one even guessed there was zucchini in it. ★★★★★“
One reader, Kara, commented: “This wasn’t just the best zucchini recipe I’ve ever tried, it was the best cake recipe as well! The zucchini here makes this moist and fudgy, almost like a brownie, but still fluffy like cake. I used cream cheese frosting and it was divine. I will be making this for birthdays in the future! ★★★★★“
Overview: Chocolate Zucchini Cake Ingredients
This decadent cake is made with fresh 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 a few key ingredients:
- 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.
- 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. We use it in chocolate zucchini bread and in this chocolate cake roll, too. You can find espresso powder in the coffee aisle at the grocery store or online.
- 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. Despite the zucchini inside, this isn’t health food, it’s dessert. Don’t try to make it into something it’s not!
- Eggs: 4 eggs bind everything together and add moisture. Remember that room-temperature ingredients are important.
- Sour Cream: Just like in chocolate peanut butter cake, you can use sour cream or plain yogurt. Either add moisture.
- Zucchini: Use 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, apple zucchini bread, and zucchini muffins, too!
Optional 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 (just like in my peanut butter chocolate chip zucchini bread), but mini chocolate chips or even dark chocolate chips pair wonderfully, too.
Let Me Show You How to Make It:
This chocolate zucchini cake comes together quickly and easily, just like my regular zucchini cake. 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 the recipe Notes section for details.
- Need cupcakes instead? This recipe yields about 24–30 cupcakes. See recipe Notes.
Chocolate Frosting
We’re topping and filling this chocolate zucchini cake with smooth, silky, and creamy chocolate buttercream. You’ll use my favorite chocolate buttercream recipe, but increase the quantity as directed in the recipe card below.
How to Assemble a Layer Cake
If you’re new to assembling and layering cakes, or if you just need a refresher, see my How to Assemble a Layer Cake video tutorial. The quick video guide will walk you through how to stack and decorate it.
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 Wilton 1M for the pictured piping:
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
- Chocolate Lava Cakes
- Flourless Chocolate Cake
- Chocolate Cake
- Chocolate Cupcakes
- Homemade Brownies
- Inside Out Chocolate Chip Cookies & Double Chocolate Chip Cookies
Chocolate Zucchini Cake
- 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 the best chocolate frosting—you won’t even taste the vegetables!
Ingredients
Cake
- 2 cups (250g) all-purpose flour (spooned & 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 (about 360g) shredded zucchini (lightly blotted; see recipe Note) (2 medium zucchini, about .75–1 lb.)
- 1 cup (180g) semi-sweet chocolate chips (regular or mini)
Chocolate Buttercream
- 1 and 1/4 cups (282g) unsalted butter, softened to room temperature
- 3 and 1/2 cups (420g) confectioners’ sugar
- 3/4 cup (62g) unsweetened cocoa powder (natural or Dutch-process)
- 3–5 Tablespoons (45–75ml) heavy cream (or half-and-half or whole milk), at room temperature
- 1/4 teaspoon salt
- 1 teaspoon pure vanilla extract
- optional for decoration: chocolate chips and/or chocolate sprinkles
Instructions
- Preheat oven to 350°F (177°C). Grease two 9-inch round 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, 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 attachment, beat the oil, granulated sugar, brown sugar, eggs, sour cream, and vanilla together until combined. Add the zucchini and mix to incorporate. Add the dry ingredients to the batter and beat on medium speed until completely combined. Fold in the chocolate chips. Batter will be slightly thick.
- Pour batter evenly into cake pans. Bake for around 28–32 minutes or until the cakes are baked through. To test for doneness, lightly poke the top of the cake with your finger—if it bounces back instead of leaving , the cake is done. Or you can insert a toothpick into the center of the cake—if it comes out clean, it’s done.
- Set the cakes on a cooling rack and let cool in the pans for 1 hour. After 1 hour, remove the cakes from the pans, discard the parchment rounds, and let the cakes finish cooling directly on the rack. The cakes must be completely cool before frosting and assembling.
- Make the buttercream: With a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium speed until creamy, about 2 minutes. Add confectioners’ sugar, cocoa powder, 3 Tablespoons of cream, salt, and vanilla. Beat on low speed for 30 seconds, then gradually increase to high speed and beat until it’s smooth and creamy. Do not over-whip. Add 1/4 cup more confectioners’ sugar or cocoa powder if frosting is too thin or 1–2 more Tablespoons of cream if frosting is too thick. (I usually add 1 more.) Taste. Add another pinch of salt if desired.
- 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, cake turntable, or serving plate. Evenly cover the top with a heaping cup of frosting. Top with 2nd cake layer and spread the remaining frosting all over the top and sides. Pipe any leftover frosting on top. (I used Wilton 1M tip.) Decorate with chocolate sprinkles or chocolate chips if desired. Slice and serve.
- Cover leftover cake and store at room temperature for up to 2 days or in the refrigerator for up to 5 days.
Notes
- 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.
- Special Tools (affiliate links): Box Grater | Glass Mixing Bowls | Electric Mixer (Handheld or Stand) | 9-inch Round Cake Pan | Cake Turntable | Wilton 1M Piping Tip | Piping Bag (Reusable or Disposable) | Cake Carrier (for storage)
- 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!
- 9×13-inch Cake: Interested in making a sheet cake instead? This batter will fit into a 9×13-inch pan. The bake time is long—at least 45 minutes to ensure the thick cake is baked through. Same oven temperature.
- Non-Chocolate Zucchini Cake: Looking for zucchini cake without chocolate? Here is my regular zucchini cake topped with brown butter cream cheese frosting.
- 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.
Instead of cake, try these as cupcakes! Directions in the recipe Notes above.
Reader Comments and Reviews
Excellent cake! I made 1.5× the recipe and baked a 2 layer, 9″×13″ cake. I served it to 30 people and everyone loved it, even the zucchini-averse kids. I will definitely make this again.
I bake several times a week and always in search of the “best” in each dish. This is hands down the absolute best chocolate cake recipe I have ever made! Easy enough that my 10 year old granddaughter was able to
help, even with grading the zucchini. Thanks Sally! It is one recipe that I won’t have to look any further for.
However I may have to add gardening to my list to always have zucchini on hand.
As my great nephew that is 6 says
” It’s the best cake that I’ve ever had!”
I agree!
Hi! Just wondering if you or anyone has made this recipe vegan by using egg replacement and non dairy sour cream and butter?
Made cupcakes with this recipe. Rich chocolate taste, moist and delicious. No frosting needed. Topped each cupcake with 2 candied walnuts. I think the frosting would have made it too sweet for my family. Had a friend drop by and he ate 4 with coffee while we had a chat. Thats how good they are! Definately dont forget to pat the zucchini dry! Will make these again!! Thank you
This amazing recipe won me first place at the state fair! IT’S SO GOOD! Sally, you never cease to amaze me. Thank you for your dedication to making your recipes foolproof.
I just finished making this recipe and had to try a piece right away. It is moist and had a wonderful deep chocolate flavor. A fantastic way to use zucchini. Thank you for posting it.
I made this today and copied your design! So easy to frost I was surprised! Didn’t even need a skim coat!
I filled with some fresh cherries and a jam I made with cherries from my own trees
Yum
I’ve made so many of Sally’s variations of chocolate cake… and they NEVER disappoint. Always a fantastic chocolate flavor, and they bake up perfectly every time. This cake was no exception. As soon as I watched the new video, I knew I had to bake this next. Very glad I did. It was delicious. What I especially liked was the thickness of the layers. I’ve found lately that many cakes have layers that are just too thin, so this was much better in that respect.
this would be so much better without the chocolate chips it makes it way to sweet.
Hi Kathy, you can simply omit the chocolate chips if desired.
Oh my Goodness!! I’ve been making Chocolate Zucchini cake for many years same recipe..I like to try different things.
No trace of the fresh Zuke right out of my Garden, super moist and I’m not big of frosting..but this chocolate buttercream is a WINNER!! SUCH A GREAT CAKE!!!
I just made this and it is still a little warm. I made 1 8×8 square layer, 12 cupcakes, 4 mini loaves and 1 small thin mini square layer. It is very delicious! No icing! We ate some right out of the oven. Ha! I cooled the rest and am going to freeze it.
Chocolate Zucchini cake. At 76 years old I am now learning how to prepare my meals. I have a bumper crop of yellow crook neck squash, but no zucchini, from the garden. I want this cake to be my first attempt of cake making. Can I get away with the yellow squash in lieu of the zucchini?
Absolutely!
Delicious! I made 1/2 the recipe with Robin Hood gluten free flour. I made cupcakes. Then I made the full recipe with a pastry cream filling between the layers. I decorated it for our daughter’s anniversary. Everyone loved it.
I have made these many times with Bobs red mill gluten free flour and they come out so good everyone loves them and the best part you can`t tell there gluten free 🙂
Thanks so much for sharing this, Nora!
Can you use frozen grated zucchini? If yes do you use the liquid that separates out ?
Hi Debbie, You can use frozen zucchini. Thaw, then squeeze out most of the excess liquid.
The flavor on the cake is phenomenal – rich, moist, chocolatey deliciousness! Frosting got rave reviews, too. I did the 9×13 sheet pan and was glad I checked early, it was thoroughly done at 30 minutes (at 350) so that would be my only thing to mention but this is 100% a keeper. Great recipe!
I have made this multiple times. It’s wonderful! My kids request this cake.
Your recipes are the best ! Question do you think Ican put buttercream white icing in the middle and the chocolate on the outside? My son request not sure about that ummm ♀️
Hi Colette, you certainly could do that, but that’s really a matter of personal preference! You could try halving this recipe for vanilla buttercream, but you will likely still have some extra if you are only using it between the cake layers.
I have made this cake at least 5 times or various events/ family parties and everyone always LOVES it! I use raspberry jam in between the layers and have frosted with vanilla and chocolate buttercream frostings and both are amazing. Highly recommend!!!!
Really moist cake!
The first time I made it, I could taste the zucchini, so the second time I made it, I peeled the zucchini before grating, which made it taste great.
My cakes took longer to bake. Is the temperature stated for a fan assisted oven?
Hi Sarah, We always recommend conventional settings for baking (not convection/fan). The flow of air from convection heat can cause baked goods to rise and bake unevenly and it also pulls moisture out of the oven. If you do use convection/fan settings for baking, lower your temperature by 25 degrees F and keep in mind that things may still take less time to bake.
Absolutely beautiful, decadent cake. Made this for Easter and everyone loved it. I made it a day ahead and assembled it the next day. Still amazing and full of moisture.
Looks so delicious!! Can I replace the canola or vegetable oil for avocado oil or melted butter? If so, is it still the same measurement?
Hi Jane, we don’t recommend melted butter in this recipe; you could try avocado oil, but we haven’t tested it. Let us know if you do!
I am using avocado oil in all my cakes and it is perfect. No problems.
I always make mine with melted butter and always get an amazing result. Everyone loves it!
Hi Sally! I am beyond excited to try this recipe! The only problem is I would prefer to not use canola or vegetable oil. Do you have a suggestion for a replacement
Hi Juliana! You could try avocado oil, but we haven’t tested it. Let us know if you do!
I made this cake using shredded pumpkin instead of zucchini. Delicious!
This cake is amazing! Every time I make it everyone comments on how delicious it is and it always disappears very fast!
I just started baking so i was a bit nervous to try out zucchini in a chocolate cake. I could not believe how good it turned out to be, gave me so much confidence.
You have quoted incorrect grams in the instructions for this recipe. As an example: 1 cup of flour is equal to 250 grams; 2 cups is equal to 500 grams. 3/4 of a cup of chocolate is equal to 113 grams.
Hi Barb, some ingredients weigh 250g per cup, but flour does not. Sugar, for example, weighs more than flour. 1 cup of spooned and leveled flour is 125g.
Do you have a scale? If so, weigh the ingredients for best results.
Can you use frozen grated zucchini
Hi Kristin, you can, be sure to thaw and drain before using. Enjoy!
I have made this recipe so many times for people’s birthdays and they just love it. Thank you so much for being addicted to baking sally!
Delicious chocolate cake! No evidence of three cups of zucchini in there! So good!!!