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
OMG! I added some extra zucchini and chopped walnuts. Top with vanilla ice cream and heaven! Best zucchini cake ever!
So glad you loved it, Linda!
Hi! Can this recipe be baked using two loaf pans?
Hi Sue, This would work well divided between two loaf pans. Fill them half way, and use any leftover batter for a few cupcakes. We’re unsure of the exact bake time.
GREAT RECIPE SO FAR. MADE IT WITH MY 11 YEAR OLD. IT’S BEEN IN THE OVEN FOR OVER HALF AN HOUR BUT STILL WET. IS THIS BECAUSE WE’RE USING A BUNDT PAN? WHAT TIME SHOULD IT BAKE WITH A BUNDT PAN?
Hi Dana, we’re unsure of the exact bake time for a Bundt cake, but it will take well over the time needed for the cake layers. Keep a close eye on it and use a toothpick to test for doneness.
Do you think you could freeze the cupcakes. Got loads of zucchini now would love to enjoy this recipe even longer
Hi Antonia, absolutely! We recommend freezing them without the frosting, if possible, for up to three months. You can also freeze them with the frosting, but it may come a bit separated from the cupcake when thawing out.
Definitely the best chocolate cake recipe I’ve ever made, so dense and moist! I made the cupcakes, they were done in about 15 minutes @350*. I topped them with homemade coffee frosting. OMG delicious! Love your recipes!
Hi Sally, can I use this recipe for cake pops?
Hi Lana, We don’t see why that wouldn’t work. Let us know if you try it!
I made this as a sheet cake two weeks ago for some neighbors and they loved it. They are throwing a party and requested this over any other bake goods I’ve shared over the years. I’d like to make a layer cake but only have 8″ cake pans. Has this been tried in that size? If so, what would I need to do differently?
Hi Tracie! 2, 8 inch pans will work just fine for slightly thicker layers. The bake time may be a few minutes longer to account for the thickness, but use a toothpick to test for doneness. So glad this one is a hit for you!
Thank you Lexi.
Loved this recipe! I made it in a Bundt pan and extended cooking time 10 minutes. I also made a chocolate grenach for the topping. Best chocolate cake ever!!
Excellent cake!! In fact, it’s one of the best chocolate cakes Ive ever had!
This chocolate cake is delicious – moist, flavorful, and not dense. Plus the zucchini – quilt removal!!!
I made this cake and frosting yesterday and Ohhhh my gosh!! It’s So chocolaty it’s obscene. The texture is absolutely perfect!
Pure deliciousness! (If that’s even a word)
: ). Thank you so much for this fabulous recipe.
I have enjoyed this recipe so many times. It is my go to chocolate cake. Just wondering if I could make it with gluten free flour?
Hi Melissa, so glad you enjoy this recipe. We don’t have any experience baking with gluten free flour but other readers have reported back that they use it successfully in our recipes. Let us know if you try it!
I don’t see the amounts for the choc. Buttercream frosting.lo
Hi Lorrie, you’ll want to use the chocolate buttercream from this cake recipe. Enjoy!
I made this a few days ago, its gone now obviously. Just absolutely delicious. I made it exactly as written except for the espresso powder which I didn’t have. I just used plain unbrewed coffee. I thought adding that might make the cake a bit grainy, but nope….it turned out perfect. Baked it in a 9×13 inch pan for 45 minutes as per directions. Will definitely make again and pass the recipe along.
I made this cake for my husband’s birthday & WOW is it spectacularly good!! And even better the next day! The chocolate buttercream icing is the best I’ve ever made. My grandchildren couldn’t stop dipping into the bowl as I was mixing it. Don’t hesitate to make this one – it’s so, so delicious! Thank you Sally!
This recipe was hands down the BEST chocalate cake I’ve ever made. We wanted to eat it warm, so we decided to forego the frosting and just put a dollop of whipped cream on each serving. OMG!!
This cake was delicious I made GF due to being a celiac. I added xantham gum and did 1/2 oil and 1/2 apple sauce. Used my own frosting as I find the buttercream too sweet for me.
Absolutely LOVED this cake along with the chocolate buttercream frosting. The only substitution I made was to use organic coconut oil instead of the canola/vegetable oil. I’m not a chocolate cake fan at all but this is superb. My husband is very particular about chocolate cakes and he gave this one a big thumbs up. I baked it in a 9×13 glass baking dish for 37 minutes and it was perfectly done.
Can I substitute unsweetened applesauce for the oil in this recipe?
Hi Connie, we haven’t tested it, but many readers have commented that they’ve had great success with substituting applesauce for half the oil. Let us know if you try it and how it turns out!
I have an abundance of garden zucchini which led me here. I love this chocolate cake so much I could cry. I am not usually a chocolate cake fan….but this is something extra special!! Pair it with your chocolate buttercream and it’s phenomenal. Thank you for another delicious recipe!
Can you substitute the sugar for stevia or some other healthier sweetener?
Hi Alisa, We’d love to help but we are not trained in baking with sugar substitutes. For best taste and texture (and so you don’t waste your time trying to adapt this recipe since it may not work properly), it may be more useful to find a recipe that is specifically formulated for sugar substitutes. Thank you!
I don’t have espresso powder on hand. Can I add in room temp coffee instead? Where would I sub that for some liquid, the oil?
Hi Mandi, if you don’t have any on hand, you can simply omit it. We don’t recommend the added liquid from coffee. It will still be delicious and plenty chocolatey!
I just put in about a rounded teaspoon of instant coffee granules instead of the espresso.
Have you ever tried making this with frozen zucchini? We have an overflow of zucchini in our garden right now, and I’m wondering if I could go ahead and shred the zucchini and freeze it, and then use it in the cake at a later date.
Absolutely! Thaw and drain excess moisture out of the thawed zucchini before using.
I have the cake in the oven now. Can I suggest an edit to the recipe? Please put blotting of the zucchini either in your ingredient list or in the ‘make the cake’ paragraph. I did not see the zucchini blotting before adding to the oil ingredients. I hope the cake comes out okay with additional bake time.
Me too
I tend to weigh my ingredients (thank you for providing them!) and King Arthur’s website states that 1 cup of shredded zucchini weighs between 121 and 150 gms. For the 3 cups for this recipe, that means between 363 and 450 gms. That’s quite a spread. Would you recommend going with the lesser amount? Or would it still work with the larger amount?
Hi Barbara, it will be about 3 medium zucchinis. Anywhere in that range should work!
I’ve made dozens of chocolate cakes over the years, and this is the BEST chocolate cake I’ve ever made. It came out looking exactly like the picture. You can SEE the texture. Moist, soft, incredible. I worried I might feel the texture of the zucchini while eating it, but nope! Sally is right that you would never know there is zucchini in it. It’s decadent and perfect in flavor and texture. This will be my go-to chocolate cake from now on!
Thank you so much for the positive feedback!
This was delicious! I made it exactly as written, so I thought, but realized after it was in the oven and half baked I forgot the oil. It was crazy good, so I will omit the oil for now on. My husband loved it!! Thank you for a great recipe!
Lovely moist and flavorful cake! I made it gluten free by replacing the flour with 50% corn starch and 50% rice flour and a pinch of xanthum gum, and it turned out perfectly!
This is the beeeeessssst chocolate cake recipe I’ve ever made! You couldn’t taste the zucchini at all, and it was even better the next day after coming out of the fridge all dense and thick. 1000/10 would definitely recommend
The best chocolate cake ever Love Love ! Thanks just addicted to all your recipes!
Perfect chocolate cake. Thank you for all your recipes. I’ve used them since I graduated high school.
This cake was mouthwatering! I completely omitted the brown sugar and it was perfect. I topped it with marscapone icing (250g marscapone, 2-3 Tbl icing sugar, 2-3 tsp vanilla essence mixed together), which made it extra moist.
Towards the end of the cooking time I covered the cake with foil so it didn’t burn. Delicious!
I have not yet made this but I was wondering if someone calculated the calories? And yes, I do realize that you get some good nutrition from all of the zucchini…..just wondering about the fat, sugar and calories 🙂 Thanks.
Hi Sheri, 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: https://www.verywellfit.com/recipe-nutrition-analyzer-4157076