Chocolate Zucchini Cake

I’ll be honest—I didn’t expect much the first time I made this chocolate zucchini cake. I was just trying to use up a couple of zucchinis sitting in the fridge.

But what came out of the oven? It completely surprised me. Moist, soft, deeply chocolatey, and somehow better than most cakes I’d made before—and I’ve baked a lot.

No one guessed there was a vegetable involved. Not even the picky eaters in my house. They just cleaned their plates and asked if there was more.

What I love about this cake is how simple it is. You don’t need fancy tools or weird ingredients. Just basic pantry stuff, some grated zucchini (nothing complicated—just grab a grater), and a little mixing.

The zucchini melts right into the batter, working behind the scenes to keep the cake from drying out. You don’t taste it. You don’t see it. But without it, the cake just wouldn’t be the same.

And that frosting? It’s rich, creamy, and smooth as silk. I go all in with a generous layer, then cover the top with mini chocolate chips. Not just for looks—they give it a little crunch and a whole lot of chocolate in every bite.

If you’ve never baked with zucchini before, this is a solid place to start. It doesn’t feel like you’re doing anything different—just making a really good chocolate cake. But the result?

It’s the kind of dessert you make once, and then keep coming back to every time you want something easy, reliable, and ridiculously good.

Table of Contents

Chocolate Zucchini Cake Recipe

Ingredients

For the Cake:

2 cups (250g) all-purpose flour, sifted
3/4 cup (75g) unsweetened cocoa powder (preferably Dutch-processed for deeper color)
1 ½ teaspoons baking powder
1 teaspoon baking soda
1 teaspoon fine salt
1 ¾ cups (350g) granulated sugar
¾ cup (180ml) neutral oil (like sunflower or vegetable)
3 large eggs, at room temperature
2 teaspoons pure vanilla extract
1 cup (245g) plain Greek yogurt
2 ½ cups (320g) finely grated zucchini (do not peel; squeeze lightly to remove excess moisture)
½ cup (120ml) brewed coffee or hot water (coffee enhances the chocolate flavor but won’t taste like coffee)

For the Frosting:

1 cup (230g) unsalted butter, softened
½ cup (45g) unsweetened cocoa powder (sifted)
3 cups (360g) powdered sugar, sifted
¼ cup (60ml) whole milk or cream, room temperature
1 teaspoon pure vanilla extract
Pinch of fine salt

For the Topping:

1 cup (170g) semisweet mini chocolate chips

Instructions

Set your oven to 175°C (350°F). Grease a 9×13-inch (23x33cm) baking pan with oil or butter and line the bottom with parchment paper for easy release.
In a large bowl, whisk together flour, cocoa powder, baking powder, baking soda, and salt. Make sure the cocoa and flour are fully combined without lumps.
In a separate bowl, whisk sugar and oil until well blended. Add eggs one at a time, whisking after each addition. Stir in vanilla and Greek yogurt until smooth.
Fold the grated zucchini into the wet mixture. Add the dry ingredients gradually, stirring until just combined. Pour in the coffee (or hot water) and stir gently until the batter is smooth and slightly loose. Do not overmix.
Pour the batter into the prepared pan and level the top. Bake in the center of the oven for 35–40 minutes or until a toothpick inserted in the center comes out clean. The top should be springy and slightly glossy.
Allow the cake to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before frosting.
Beat the softened butter in a mixing bowl until creamy and pale (about 3–4 minutes). Add cocoa powder and beat until smooth.
Gradually add powdered sugar, one cup at a time, mixing on low to avoid splatter. Pour in milk, vanilla, and salt, then beat on high speed for 2–3 minutes until light, fluffy, and spreadable.
Once the cake is completely cool, spread the chocolate frosting evenly over the top using an offset spatula or back of a spoon.
Immediately after frosting, sprinkle the mini chocolate chips generously across the top, pressing them in very gently so they adhere.
Cut into squares and serve. Store leftovers in an airtight container at room temperature for up to 3 days, or refrigerate for up to a week.

How Do I Make Chocolate Zucchini Cake Moist?

Keeping the cake soft and moist is all about smart choices and the right balance of ingredients.

Use oil, not butter: Oil keeps the cake more tender than butter, even after a day or two.
Don’t skip the yogurt: It adds richness and moisture without making the batter heavy.
Grate zucchini finely: Smaller shreds mix better into the batter and help with even moisture.
Don’t overbake: A few extra minutes can dry it out. Check with a toothpick early.
Avoid squeezing too much water: Some moisture from zucchini is needed for the right texture.
Let it cool properly: Trapping steam by covering it while warm can ruin the crumb.

Should I Squeeze The Water Out Of The Zucchini?

A little moisture is good, but too much can make the batter soggy. Here’s what to do:

Light squeeze only: Gently press the grated zucchini between paper towels or your hands.
Don’t wring it dry: You want it damp, not dripping. The natural water helps the cake stay soft.
If zucchini is very watery: Let it sit for 5–10 minutes after grating, then blot it.

Can I Make Chocolate Zucchini Cake Without Eggs?

Yes, you can, and it still turns out soft and tasty. Here are some common replacements (use 1 per egg):

Plain yogurt: 1/4 cup
Mashed ripe banana: 1/4 cup
Applesauce: 1/4 cup, unsweetened
Chia seed gel: 1 tablespoon chia seeds + 3 tablespoons water (let sit 10 minutes)
Flaxseed meal: 1 tablespoon flaxseed meal + 3 tablespoons water (let sit 10 minutes)

Is Chocolate Zucchini Cake Healthy?

It depends how it’s made, but in general:

It uses zucchini: Adds fiber, vitamins, and moisture naturally.
No need for too much fat: Zucchini replaces some oil or butter.
Can be made lighter: Use less sugar, whole wheat flour, or skip frosting.
Still a dessert: It’s chocolate cake, so enjoy in balance.

How Fine Should I Grate The Zucchini For Cake?

Smaller shreds melt right into the cake and keep the texture smooth.

Use the fine side of a box grater: The zucchini will disappear in the batter.
Avoid big chunks: Large pieces can make the texture weird and bake unevenly.
Don’t use a food processor: It can turn zucchini into mush.

Why Is My Chocolate Zucchini Cake Too Wet?

If your cake turned out heavy or soggy, these are the most common reasons:

Too much zucchini water: Always squeeze it lightly before adding.
Over-measuring wet ingredients: Use proper cups or a scale.
Not baked long enough: Check the center with a toothpick.
Too many egg substitutes: Using too much banana or applesauce can over-moisturize the batter.

Can I Make This Cake Gluten-Free?

Yes, it works well if you use the right flour mix. Here’s how to do it:

Use a 1:1 gluten-free flour blend: Make sure it includes xanthan gum or guar gum.
Avoid almond or coconut flour: These need different ratios and can change the result.
Mix well but don’t overbeat: Gluten-free batters can get gummy fast.
Watch baking time: Sometimes takes a few minutes longer.

Do Kids Eat Chocolate Zucchini Cake?

Yes—most kids don’t even know zucchini is in it! Here’s what makes it kid-approved:

It tastes like regular chocolate cake: Rich, soft, and chocolatey.
Zucchini is hidden: If grated fine, they won’t even see it.
Sweet but not too sweet: It’s easy on the sugar and great for lunchboxes.
Frosting helps: A smooth chocolate frosting on top makes it extra fun.

Should Chocolate Zucchini Cake Be Stored In The Fridge?

It depends how long you’re keeping it:

For 1–2 days: Store at room temperature in an airtight container.
More than 2 days: Keep it in the fridge, especially if it’s frosted.
Keep covered: So it doesn’t dry out.
Bring to room temp before serving: Cold cake can feel firm—softens up after sitting out.

Can I Freeze Chocolate Zucchini Cake?

Yes, and it freezes really well without losing flavor or texture.

Cool completely: Never freeze while warm or the top will get sticky.
Wrap tightly: Use plastic wrap and foil or a freezer-safe bag.
Freeze without frosting: It stores better that way. Add frosting after thawing.
Freeze in slices: Makes it easy to take out just what you need.
Thaw on the counter: Let it come to room temperature naturally.