Chocolate Zucchini Cake

If you’ve ever wondered what zucchini does in a cake, this triple chocolate zucchini cake shows off the magic perfectly. Expect a super moist, tender slice hiding grated zucchini so cleverly you won’t even spot it—except in the gorgeous texture it adds. This cake delivers chocolate on three levels: cocoa powder in the batter, melty semisweet chocolate chips folded inside, and a luscious chocolate buttercream spread on top.

It’s a simple, crowd-pleasing recipe that fits right into busy schedules. You’ll spend about 15 minutes prepping the ingredients (including grating zucchini, which is easy with a quick hand or box grater) and then bake it for 45 to 50 minutes until a toothpick comes out clean. This recipe yields around 12 generous servings — perfect for family dinners, potlucks, or cheering up any day.

• Texture & flavor: rich, moist thanks to zucchini and buttermilk, bursting with chocolate flavor from cocoa and chips.
• Time: about 15 minutes prep, 45–50 minutes baking (around 1 hour and 5 minutes total).
• Flexibility: can easily be baked in a Bundt pan, made into cupcakes, or topped with a lighter glaze instead of the full buttercream. Also great for freezing or making ahead.

Keep reading for the full ingredient list, step-by-step instructions, handy tips, and creative swaps to help you confidently whip up this triple chocolate zucchini cake masterpiece.

What Makes It Irresistible

• This triple chocolate zucchini cake recipe doubles down with cocoa powder and chocolate chips in the batter — and don’t forget the chocolate frosting on top!

• It’s a moist, tender, crave-worthy cake that easily feeds a crowd and gets everyone smiling.

You seriously need to try this triple chocolate zucchini cake! It’s straightforward to make and incredibly delicious. Plus, it sneaks in some veggies to boost the nutrition on a dessert that never disappoints. If you love baking with zucchini, you’ll also enjoy our Irresistible Zucchini Bread for an anytime, sliceable treat. Out of all the chocolate cake recipes I’ve shared, this one is a standout—and you’ll feel good about serving it to your family too!

Ingredients and Tools

• 2 1/4 cups all-purpose flour
• 1/2 cup unsweetened cocoa powder
• 1 teaspoon baking soda
• 1 teaspoon salt
• 1 3/4 cups granulated sugar
• 1/2 cup (1 stick) unsalted butter at room temperature
• 1/2 cup vegetable oil
• 2 large eggs
• 1 teaspoon vanilla extract
• 1/2 cup buttermilk well shaken
• 2 cups grated zucchini unpeeled
• 1 cup semisweet chocolate chips
• 3/4 cup (1 1/2 sticks) unsalted butter at room temperature
• 3 cups confectioner’s sugar sifted
• 1/2 cup unsweetened cocoa powder
• 1 teaspoon vanilla extract
• 2-4 tablespoons whole milk

How to Make the Cake

1. Preheat oven to 325°F and lightly spray a 9×13-inch baking pan with nonstick cooking spray.
2. Grate 2 cups unpeeled zucchini.
3. Whisk together 2 1/4 cups all-purpose flour, 1/2 cup unsweetened cocoa powder, 1 teaspoon baking soda, and 1 teaspoon salt.
4. Use an electric mixer to combine 1 3/4 cups granulated sugar, 1/2 cup (1 stick) softened unsalted butter, and 1/2 cup vegetable oil until smooth.
5. Beat in 2 large eggs one at a time, then stir in 1 teaspoon vanilla extract.
6. Add the dry ingredients and 1/2 cup well-shaken buttermilk alternately in three batches, beginning and ending with the dry ingredients.
7. Gently fold in the grated zucchini and 1 cup semisweet chocolate chips.

8. Pour the batter into the prepared pan and smooth the top with a spatula.

   

9. Bake 45–50 minutes, or until a toothpick inserted into the center comes out clean; let the cake cool completely.
10. Beat 3/4 cup (1 1/2 sticks) softened unsalted butter until creamy for the frosting.
11. Gradually mix in 3 cups sifted confectioner’s sugar and 1/2 cup unsweetened cocoa powder until smooth.
12. Add 2 tablespoons whole milk and beat on medium speed for 2–3 minutes, adding additional milk 1 tablespoon at a time until the frosting reaches a spreadable consistency.
13. Spread the frosting evenly over the cooled cake.

Tips for Best Results

Thanks to the grated zucchini and buttermilk, this cake comes out incredibly moist with amazing flavor. But be sure not to underbake it! The extra moisture means it needs a bit more time baking than your usual chocolate cake. Since ovens vary, rely on the trusty toothpick test to know when it’s done.

Making it in a Bundt pan? You’ll want to add about 5 extra minutes to the baking time because of the pan’s depth. Don’t forget to use a nonstick spray with flour to avoid sticking—I personally use Pam Baking spray (just my experience, not an endorsement).

When baking as a Bundt, I usually go for a lighter powdered sugar glaze instead of the rich buttercream frosting. Just a little drizzle finishes it perfectly.

Zucchini notes: This cake shines with freshly grated, unpeeled zucchini. Zucchini varies—you may find some that are wetter or drier. I usually buy a couple of zucchinis just in case. If your zucchini skin feels tough like a melon rind, peeling it before grating is a smart move. Otherwise, leave the skin on for extra color and nutrients. If you’re looking for another sweet way to use grated zucchini, try this Apple Cinnamon Zucchini Bread.

Cocoa powder quality matters: Using a decent cocoa powder really affects the taste. I skip the cheapest in favor of something mid-priced with a good chocolate flavor.

Chocolate chips: Walnuts are a tasty alternative to chocolate chips if you want a little crunch. I sometimes swap in nuts or a mix to shake things up.

The best part? This cake feeds a crowd and brings lots of smiles—perfect for church events, picnics, or casual family barbecues. For a quick chocolate treat that travels well to potlucks, try these Easy 10 Minute Chocolate No Bake Cookies. Enjoy it plain or with a scoop of vanilla ice cream or whipped cream for an extra treat!

Flavor Swaps and Add-Ins

Want to mix things up or make this cake your own? Here are some easy swaps and additions that keep it moist and delicious. Craving a non-chocolate zucchini bake instead? Try our Carrot Apple Zucchini Bread.

• Swap out semisweet chocolate chips for 1 cup chopped walnuts for a lovely nutty crunch, or try white chocolate or peanut butter chips to change the flavor profile.
• If you prefer, bake the batter in a Bundt pan (adding a few more minutes baking time) and finish with a simple powdered sugar glaze instead of rich frosting.
• Divide the batter into cupcake tins and bake for 18 to 22 minutes for portable treats, or split between two 9-inch round pans to make a layered cake (adjust bake time and check doneness carefully).
• For a lower-fat cake, replace the 1/2 cup vegetable oil with 1/2 cup unsweetened applesauce; texture will be a bit different but still tasty.
• Go gluten-free by swapping all-purpose flour for an equal amount of a 1:1 gluten-free flour blend.
• Boost chocolate flavor with 1 teaspoon of instant espresso powder mixed into the dry ingredients, or stir in 1 cup shredded coconut for a fun texture twist.
• If you prefer Dutch-processed cocoa powder (which is less acidic), try mixing it with natural cocoa or add a little baking powder to help with rising, but natural cocoa powder generally gives the best results.

How to Store and Freeze

• How long does this zucchini cake last in the fridge? Thanks to the zucchini, this cake stays beautifully moist for up to 3 days when stored properly. Make sure it’s completely cooled before covering tightly, and wrap cut edges with cling wrap to keep it fresh.

• Can you freeze this cake? Absolutely! This triple chocolate zucchini cake freezes wonderfully. I recommend wrapping it in several layers of cling wrap and then placing it in a freezer-safe bag for the best protection. Freeze with or without frosting depending on your plans. I often wrap individual slices for easy thawing.

  • To thaw, just move it from the freezer to the fridge the day before you want to serve.
• Make-ahead tips: This cake only takes 15 minutes of hands-on prep, so it’s great for making a day ahead. If you need to prepare it farther in advance, freezing is your best bet to keep that perfect moisture.

Common Questions Answered

Q: Do I need to peel the zucchini? No, the recipe works best with unpeeled zucchini. The skin adds nice color and nutrients. If the skin is really thick or tough, peeling is fine.

Q: Should I squeeze the grated zucchini to remove moisture? Usually, no. The moisture helps keep the cake super tender. If your zucchini is very watery, a gentle pat or light squeeze can help, but don’t remove all moisture. For savory bakes like a classic zucchini slice, you’ll usually squeeze out more liquid—see this zucchini and bacon slice recipe for that technique.

Q: How do I know when the cake is done? Use the toothpick test: insert a toothpick in the center—it should come out clean or with a few moist crumbs, but no wet batter. Because of the zucchini’s moisture, this cake may need the full 50 minutes, so start checking around 45 minutes.

Q: Can I make this dairy-free or egg-free? Yes! For dairy-free, swap butter for a dairy-free butter substitute and use non-dairy milk mixed with 1 teaspoon vinegar to mimic buttermilk. For egg replacements, use a commercial egg replacer or mix 2 tablespoons ground flaxseed with 6 tablespoons water per egg (texture will be a little different).

Q: How should I store and freeze the cake? Store covered at room temperature for up to 2 days or in the fridge up to 3 days. Freeze tightly wrapped (with or without frosting) and thaw slowly in the fridge before serving.

Q: Why did my cake’s center sink? Common reasons include underbaking, opening the oven door too early, or too much leavening agent. Make sure the cake reaches doneness before pulling it out and follow the recommended baking times.

Q: Can I substitute the chocolate chips? Yes, walnuts make a delicious swap. You can also try chopped nuts, dried fruit, or different types of chocolate chips based on your preferences.