Chocolate chip zucchini cake is a moist vanilla sheet cake filled with mini chocolate chips. It's perfect for summer birthdays and parties!
This chocolate chip zucchini cake starts with a perfectly sweetened vanilla cake base that's filled with mini chocolate chips. The frosting is a classic whipped buttercream that's filled with more mini chocolate chips and has a light, fluffy texture.
It's perfect any time of year and makes a great use of all that summer garden zucchini! Serve chocolate chip zucchini cake for birthdays, celebrations, or just because. This recipes makes a 9x13 cake that can easily feed 16 to 24 guests.
Cake ingredients and substitutions
- Flour - All purpose flour adds structure to your cake. I have not tested this recipe with other types of flours, so I don't suggest making any substitutions. Baking is an exact science and altering main ingredients can change the density and texture of your cake.
- Leavening - You'll need baking powder for this recipe. It cannot be substituted with baking soda - the two are not interchangeable.
- Salt - Enhances the flavor of your cake without making it salty. I don't recommend omitting the salt.
- Zucchini - You'll need two cups of finely shredded zucchini for this recipe. This is about 2 medium or 3 small zucchini. I highly recommend weighing your shredded zucchini for best accuracy. Two cups of shredded zucchini (with the liquid) equals about 270 grams.
- Sugar - Adds sweetness and moisture to the cake. We're using all granulated sugar in this recipe.
- Oil - Adds moisture to the cake.
- Eggs - Add structure and moisture to the cake.
- Vanilla - Enhances the flavor of your cake.
- Chocolate chips - I recommend mini chocolate chips because they're less likely to sink in the batter and add tiny dots of melty chocolate throughout.
Frosting ingredients and substitutions
- Butter - Unsalted butter can be substituted with salted butter (omit the salt listed in the recipe). Make sure your butter is room temperature before preparing your frosting.
- Vanilla - Enhances the flavor of the frosting.
- Salt - Enhances the flavor of the frosting and helps balance the sweetness.
- Confectioner's sugar - Confectioner's sugar combines seamlessly with the other ingredients and is a must for making buttercream frosting.
- Heavy cream - Necessary to create the light and fluffy whipped texture of this frosting.
- Chocolate chips - I added mini chocolate chips to the cake and frosting for extra chocolate flavor throughout. Feel free to omit the chocolate chips from the frosting if desired. I don't recommend substituting with regular chocolate chips because the size can make it difficult to spread the frosting smoothly over the cake.
Tips and tricks
Use room temperature ingredients - Eggs should be room temperature to incorporate seamlessly into the batter. To bring eggs to room temperature quickly, place eggs (in the shell) in a bowl and cover with warm tap water. After 10 minutes, your eggs will be ready.
Properly measure your flour - The biggest issue I see in baking is the improper measuring of flour. Scooping flour directly from a bin into a measuring cup compacts the flour, adding up to 25% extra flour to the recipe. This causes baked goods to turn out dry and bland. I highly recommend using a kitchen scale along with the gram measurements in the recipe card. If you don't have a kitchen scale, use the spoon and level method. Gently stir your flour, then spoon into a measuring cup until heaping. Level off the top with a knife.
Don't overmix the batter - There's no need to use a hand mixer or stand mixer for this recipe. The batter comes together with a bowl and a spoon. Overmixing can overwork the gluten, causing cupcakes to turn out tough and/or not rise properly.
Watch your cake, not the baking time. Ovens all run at slightly different temperatures, and if your oven runs hotter, your cake may be done faster than mine. Use visual cues to tell when your cake is done, such as the cake browning around the edges and pulling away from the pan. The cake should pop back in the center when gently pressed. If an indent is left, your cake needs more time.
Allow cake to cool completely - Before frosting or slicing, allow your cake to cool completely. Slicing into hot cake releases steam, which dries out your cake. Buttercream frosting will melt on a hot or warm cake, which is why it's important to allow the cake to cool completely.
Frequently asked questions
Regular chocolate chips can work, but create larger melty pockets of chocolate throughout the cake. They're also more likely to sink to the bottom in the cake batter. I don't recommend adding regular chocolate chips to the frosting because they're a bit too big and clunky to spread evenly over the cake.
No. For this recipe, you should not squeeze the liquid from your zucchini. We're using that liquid to add moisture and thin the batter to achieve the proper rise in the oven.
No, there's no need to peel your zucchini. The skin and flesh melt seamlessly into the cupcakes as they bake. The only sign of zucchini you'll see are the green flecks throughout the cake.
No, zucchini has a mild flavor that makes it ideal for baking. Cucumber has a fresh "melon" flavor that's much more pronounced and not ideal for hiding in baked goods. For more information: Zucchini vs Cucumber - What's the Difference?
I recommend shredding zucchini using the small or "fine" side of a box grater. The smaller pieces melt right into the cake as it bakes. A larger grate also works but adds a more noticeable texture. Here's the box grater I use: Amazon: OXO Good Grips Box Grater
This cake is prepared in a 9x13 baking pan. This quantity of batter would also work in two 8-inch or 9-inch round cake pans to make a layer cake (like my lemon zucchini cake recipe) or in a 13x18 sheet pan. Baking times will vary when using different pan sizes.
Zucchini cake will keep for 3 to 5 days in a tightly sealed container at room temperature or the refrigerator.
Yes, this cake (whole or in slices) can be frozen for up to 3 months. Thaw in the refrigerator overnight or on the countertop for 2 to 3 hours.
Chocolate Chip Zucchini Cake
- 2.5 cups (300 g) all-purpose flour
- 2 teaspoons baking powder
- 1 teaspoon salt
- 2 cups (270 g) finely shredded zucchini, do not squeeze liquid out
- 1.5 cups (300 g) granulated sugar
- 1 cup (198 g) vegetable oil
- 3 large eggs, room temperature
- 1 tablespoon vanilla extract
- 1 cup (177 g) mini chocolate chips
- 1 cup (226 g) unsalted butter, room temperature
- 1 teaspoon vanilla extract
- ¼ teaspoon salt
- 3 cups (340 g) confectioner's sugar
- ½ cup (114 g) heavy cream
- ½ cup (88 g) mini chocolate chips
- Preheat oven to 350 degrees Fahrenheit and lightly grease (or line with parchment paper) a 9x13 baking pan. Set aside.
- In a bowl, add dry ingredients: flour, baking powder, and salt. Whisk to remove clumps and set aside.
- In a separate bowl, add wet ingredients: shredded zucchini (do not squeeze liquid out), granulated sugar, oil, eggs, and vanilla extract. Stir until incorporated.
- Add dry ingredients to wet ingredients and stir until just incorporated (do not overmix). Add chocolate chips and stir to combine.
- Pour cake batter into prepared 9x13 baking pan and bake for about 28 to 34 minutes, or until the center pops back when gently pressed, or a toothpick inserted into the center comes out with crumbs, not wet batter.
- Allow cake to cool completely to room temperature before frosting or slicing.
- In a large bowl, add butter, vanilla extract, and salt. Using a hand mixer or stand mixer, beat until light and fluffy, about a minute.
- Add confectioner's sugar, ⅓ at a time, mixing on low speed until incorporated. Once all of sugar is incorporated, beat at medium-high speed until light and fluffy, about a minute.
- Add heavy cream and beat until light and fluffy, about a minute. Add chocolate chips and gently stir to incorporate.
- Spread frosting in an even layer onto cooled cake. Optionally, top with more mini chocolate chips.
- Frosting recipe makes a nice thick layer of frosting for your 9x13 sheet cake (as pictured). If you prefer less frosting, feel free to cut the frosting recipe in half.
- Nutrition based on slicing cake into 16 pieces. Cake can be sliced to serve 24 or more guests with smaller slices.
- Cake will keep for 3 to 5 days in a tightly sealed container at room temperature. Cake can also be frozen for up to 3 months. To thaw, place on the countertop at room temperature for 2 to 3 hours.