Chocolate Zucchini Cake

How This Moist Chocolate Zucchini Cake Uses Up Garden Zucchini

Every summer when my garden starts producing zucchini faster than I can keep up, this chocolate cake becomes my go-to. The shredded zucchini melts into the batter, making it incredibly moist without any grassy flavor. I love that I can bake it in a 9×13 pan, no fancy layers, just a generous slice of rich chocolate cake topped with a silky frosting. Pin this now so you have it ready for your own zucchini surplus.

Why You’ll Love This Easy Chocolate Zucchini Cake

• The zucchini keeps the cake super moist so it stays tender for days.
• The simple one-pan format means fewer dishes and easy serving for a crowd.
• The homemade chocolate frosting is thick, creamy, and perfectly sweet.

Key Ingredients for a Perfect Chocolate Zucchini Cake

• Unsweetened cocoa powder: Use Dutch-process or natural; both work, but Dutch gives a smoother flavor. Sift to remove lumps before measuring.
• Zucchini: Use a medium grate on a box grater. One medium zucchini yields about 1 cup grated. No need to peel, the skin blends right in.
• Buttermilk: Adds tang and activates the baking soda for a tender crumb. If you don’t have buttermilk, add 1 tablespoon lemon juice to 1 cup milk and let sit for 5 minutes.

Kitchen Tools You Need for Chocolate Zucchini Cake

• Box grater or food processor with grating disc for shredding zucchini
• 9×13-inch metal baking pan (glass works but may require longer baking)
• Stand mixer or hand mixer for making the frosting
• Sifter for cocoa powder and confectioners’ sugar

Tips for Making the Best Moist Chocolate Zucchini Cake

You’ll need about 2 cups of grated zucchini, which is one very large or two medium squash. Don’t bother peeling, the green flecks disappear into the dark batter. If your zucchini is especially watery, give it a gentle squeeze to remove some moisture, but don’t squeeze it dry or the cake will be less moist. I use all brown sugar here because it adds moisture and a deeper flavor. The combination of oil and butter gives both tenderness and richness. Be sure your eggs and buttermilk are at room temperature so they blend smoothly. Mix the batter just until the flour disappears, then fold in the zucchini and chocolate chips. Overmixing can make the cake tough. I bake in a metal 9×13 pan; glass may need a few extra minutes. Let the cake cool completely before frosting, otherwise the frosting will melt.

Expert Tips for a Perfect Chocolate Zucchini Cake Every Time

To get the most accurate cocoa measurement, spoon it into your measuring cup and level with a knife, don’t scoop from the bag, which compacts it. Sifting the cocoa with the flour removes lumps and ensures even distribution. If you want to add nuts like walnuts or pecans, fold in 1/2 cup along with the chocolate chips. For a lighter frosting, use cold milk and beat for an extra minute to incorporate more air.

Why This Chocolate Zucchini Cake Uses Both Oil and Butter

Using both oil and butter gives you the best of both worlds. Oil keeps the cake tender and moist for days, while butter adds a rich flavor that oil alone can’t match. I tested this cake with all oil and it was moist but flat in taste; all butter gave a great flavor but dried out faster. The 3/4 cup oil plus 1/4 cup butter is the sweet spot. Don’t substitute margarine, the water content can alter the texture.

Chocolate Zucchini Cake Variations to Try

If you’d like a different twist, swap the semisweet chips for dark chocolate or white chocolate chips. Add 1/2 cup shredded coconut to the batter for texture. For a gluten-free version, use a 1-to-1 gluten-free flour blend. And if you’re not a fan of chocolate frosting, a cream cheese frosting works beautifully, just reduce the sugar slightly.

Serving Suggestions for Chocolate Zucchini Cake

This cake is rich enough on its own, but a scoop of vanilla ice cream takes it over the top. For a summer dessert, serve it with fresh raspberries or a dollop of whipped cream. It also pairs well with a cold glass of milk or coffee.

How to Store Leftover Chocolate Zucchini Cake

Store leftover cake in an airtight container at room temperature for up to 3 days. If your kitchen is warm, refrigerate it for up to 5 days. Bring slices to room temperature before serving for the best texture.

How to Freeze Chocolate Zucchini Cake for Later

You can freeze this cake for up to 3 months. For best results, freeze the unfrosted cake: let it cool completely, wrap tightly in plastic wrap, then foil. When ready to serve, thaw in the refrigerator overnight and frost before serving. If already frosted, place the cake in the freezer until the frosting firms up, then wrap and freeze as above.

Best Ways to Reheat Chocolate Zucchini Cake

Honestly, this cake is best at room temperature. If you want a warm slice, microwave it for about 15 seconds, just enough to soften the chocolate chips without melting the frosting.

Frequently Asked Questions About Chocolate Zucchini Cake

Equipment

• 9x13-inch baking pan
• mixing bowls
• whisk
• spatula
• stand mixer or hand mixer
• toothpick
• sifter

Recipe

Chocolate Zucchini Cake

Print recipe Pin recipe

Prep

20 min

Cook

30 min

Total

50 min

Servings

16 servings

Cuisine

American

Course

Dessert

Ingredients

• 2 cup all-purpose flour
• 1 cup unsweetened cocoa powder (sifted)
• 2 tsp baking soda
• 0.5 tsp salt
• 1.5 cup brown sugar
• 0.75 cup vegetable oil, canola oil, or avocado oil
• 0.25 cup melted butter (cooled to room temperature)
• 0.25 cup buttermilk (room temperature)
• 3 large eggs (room temperature)
• 1.5 tsp vanilla extract
• 2 cup zucchini (shredded)
• 1 cup chocolate chips
• 0.5 cup unsalted butter (room temperature)
• 3 cup confectioner's sugar
• 0.667 cup unsweetened cocoa powder
• 0.333 cup milk
• 1 tsp vanilla extract
• pinch salt

Instructions

1. Preheat oven to 350 degrees F. Grease a 9x13-inch pan with nonstick cooking spray and set aside.
2. In a medium bowl, combine the flour, sifted cocoa powder, baking soda, and salt. Whisk together and set aside.

Nutrition (per serving, estimated)

Calories

420 kcal21% DV

Protein

6 g12% DV

Fat

22 g28% DV

Carbs

58 g21% DV

Fiber

4 g14% DV

Sodium

290 mg13% DV

% Daily Values are based on a 2,000-calorie diet (FDA). Values are estimates — see our nutrition data sources.

complete the meal

Pairs Well With

DessertZucchini Brownies