Rich Chocolate Zucchini Cake That Stays Moist for Days

This chocolate zucchini cake delivers deep chocolate flavor and a soft, tender crumb that stays moist for days. It is the kind of cake you can make any night of the week and still enjoy fresh slices for breakfast.

A cup of shredded zucchini melts into the batter, adding moisture without changing the taste. The result is a rich, fudgy cake with a crackly top and pockets of melted chocolate chips in every bite.

What Makes This Chocolate Zucchini Cake So Good

The cake has a rich chocolate flavor from cocoa powder, and the shredded zucchini keeps it incredibly moist without tasting like vegetables. Even a few days later, slices stay soft and tender, which is rare for homemade cakes.

It is the ideal back-pocket recipe for summer when zucchini is everywhere, but I bake it all year. The batter comes together in one bowl, and the chocolate chips on top melt into a glossy finish that looks as good as it tastes.

Ingredients

• 1 ¾ cups all-purpose flour: spooned and leveled, not scooped
• ¾ cup unsweetened cocoa powder: Dutch-process gives a deeper flavor
• 1 ½ teaspoons baking soda
• ½ teaspoon baking powder
• 1 teaspoon salt
• 1 ½ cups granulated sugar
• ½ cup vegetable oil: or any neutral oil
• 2 large eggs
• 2 teaspoons vanilla extract
• 1 cup buttermilk: or plain yogurt thinned with a splash of milk
• 2 cups packed shredded zucchini: no need to peel, lightly blotted with paper towels
• 1 cup semi-sweet chocolate chips: divided, half for the batter and half for the top

Substitutions and Variations

• Whole wheat flour: swap up to half of the all-purpose flour for a slightly nuttier crumb.
• Coconut oil: use melted, cooled coconut oil instead of vegetable oil if you like a hint of coconut.
• No chocolate chips: fold in ¾ cup chopped walnuts or pecans instead.
• Dairy-free: use unsweetened almond milk with 1 tablespoon vinegar instead of buttermilk, and pick dairy-free chocolate chips.
• Espresso boost: add 1 teaspoon espresso powder to the dry ingredients to make the chocolate taste even richer.

For a banana version, try my Banana Chocolate Chip Snack Cake.

How to Make Chocolate Zucchini Cake

Step 1: Mix the Dry Ingredients

Preheat the oven to 350°F (175°C) and grease a 9×13-inch baking pan. In a medium bowl, whisk together the 1 ¾ cups flour, ¾ cup cocoa powder, 1 ½ teaspoons baking soda, ½ teaspoon baking powder, and 1 teaspoon salt until no lumps remain.

The mixture should look uniform, with the cocoa evenly distributed and no white streaks of flour or baking soda.

Step 2: Whisk the Wet Ingredients

In a large bowl, whisk the 1 ½ cups sugar, ½ cup oil, 2 eggs, 2 teaspoons vanilla, and 1 cup buttermilk until smooth and well combined.

The mixture will be glossy and thick, with no visible streaks of egg yolk or oil. This step creates the base that will keep the cake tender.

Step 3: Combine and Fold in the Zucchini

Pour the dry mixture into the wet mixture and stir with a spatula just until you no longer see streaks of flour. Fold in the 2 cups shredded zucchini and ½ cup of the chocolate chips. Stop mixing as soon as the ingredients come together.

The batter will be thick and dotted with green flecks and chocolate chips. Overmixing at this stage can make the cake tough, so be gentle.

Step 4: Pour and Bake the Cake

Scrape the batter into the prepared pan and spread it into an even layer. Sprinkle the remaining ½ cup chocolate chips over the top. Bake for 30 to 35 minutes, until a toothpick inserted in the center comes out with a few moist crumbs attached.

The cake will rise and the top will develop a crackly crust. Your kitchen will smell like a bakery about 10 minutes in. Check a minute or two early if your oven tends to run hot.

Step 5: Cool and Slice the Cake

Let the cake cool in the pan on a wire rack for at least 20 minutes before slicing. This gives the crumb time to set so each piece holds together. Serve warm or at room temperature, and watch the glossy chocolate chips melt softly under the knife.

Tips for the Best Cake

• Use a box grater for the zucchini and blot it lightly with paper towels. You want the natural moisture for tenderness, not puddles of water.
• Dutch-process cocoa powder makes the chocolate flavor deeper and smoother, but natural cocoa works too.
• For an extra fudgy cake, pull it from the oven 2 to 3 minutes earlier so the center stays slightly soft.
• Let the cake cool completely before storing it, or trapped steam will make the top gummy.
• This cake freezes beautifully. Wrap individual slices in plastic wrap, then store in a freezer bag for up to 3 months.

Bake times will vary with your pan:

Storing Leftover Cake

• Refrigerate: Keep the cake tightly covered at room temperature for up to 2 days, or refrigerate for up to a week. The fridge extends the life and firms up the crumb slightly, which many people love.
• Reheating: A 15-second zap in the microwave warms it just enough to make the chocolate chips gooey again.
• Serve cold: It tastes wonderful straight from the fridge, cold and almost fudgy.

What to Serve with Chocolate Zucchini Cake

A scoop of vanilla ice cream or a dollop of lightly sweetened whipped cream balances the rich chocolate and adds a cool contrast. Fresh raspberries also work well, cutting through the sweetness with a little tartness.

Frequently Asked Questions

Can I make this cake gluten-free?

Yes, use a cup-for-cup gluten-free baking flour blend in place of the all-purpose flour.

Do I need to peel the zucchini?

No, the peel is tender and disappears into the cake. Just wash it well before shredding.

Can I turn this batter into cupcakes?

Absolutely. Fill paper liners two-thirds full and bake at 350°F (175°C) for 18 to 22 minutes, until a toothpick comes out clean.

Can I freeze this cake?

Yes, wrap slices tightly in plastic wrap, then in foil or a freezer bag. Freeze for up to 3 months and thaw at room temperature.

Chocolate Zucchini Cake Recipe

Print Recipe Pin Recipe

Prep Time 20 minutes mins

Cook Time 35 minutes mins

Total Time 55 minutes mins

Servings: 12 servings

Calories: 290

Ingredients Method Notes

Ingredients

  

• 1 ¾ cups all-purpose flour
• ¾ cup unsweetened cocoa powder
• 1 ½ teaspoons baking soda
• ½ teaspoon baking powder
• 1 teaspoon salt
• 1 ½ cups granulated sugar
• ½ cup vegetable oil
• 2 large eggs
• 2 teaspoons vanilla extract
• 1 cup buttermilk
• 2 cups packed shredded zucchini
• 1 cup semi-sweet chocolate chips, divided

Method

 

1. Preheat the oven to 350°F (175°C) and grease a 9×13-inch baking pan. Whisk the flour, cocoa powder, baking soda, baking powder, and salt together in a medium bowl.
2. In a large bowl, whisk the sugar, oil, eggs, vanilla, and buttermilk until smooth.
3. Add the dry ingredients to the wet ingredients and stir just until no flour streaks remain. Fold in the shredded zucchini and ½ cup of the chocolate chips. Do not overmix.
4. Spread the batter evenly into the prepared pan and sprinkle the remaining ½ cup chocolate chips on top. Bake for 30 to 35 minutes, until a toothpick inserted in the center comes out with a few moist crumbs.
5. Let the cake cool in the pan on a wire rack for at least 20 minutes, then slice and serve warm or at room temperature.

Notes

For clean slices that hold together, wait until the cake is completely cool. Warm cake tastes amazing but will crumble more easily. This cake is even better the next day, after the flavors settle.