Step 1

Preheat oven to 350°F (177°C). Grease two 9-inch round cake pans, line with parchment paper rounds, then grease the parchment paper. Parchment paper helps the cakes seamlessly release from the pans. (If it’s helpful, see this parchment paper rounds for cakes video & post.)

Step 2

Whisk the flour, cocoa powder, baking soda, baking powder, espresso powder (if using), and salt together in a large bowl. In another large bowl using a handheld or stand mixer fitted with a paddle or whisk attachment, beat the oil, granulated sugar, brown sugar, eggs, sour cream, vanilla, and zucchini together until combined. Pour into dry ingredients and beat on medium speed until completely combined. Beat in the chocolate chips. Batter will be slightly thick.

Step 3

Pour batter evenly into cake pans. Bake for around 25-32 minutes or until the cakes are baked through. To test for doneness, insert a toothpick into the center of the cake. If it comes out clean, it is done. Allow cakes to cool completely in the pans set on a wire rack. The cakes must be completely cool before frosting and assembling.

Step 4

First, using a large serrated knife, slice a thin layer off the tops of the cakes to create a flat surface. Discard (or crumble over ice cream!). Place 1 cake layer on your cake stand, cake turntable, or serving plate. Evenly cover the top with frosting. Top with 2nd layer and spread the remaining frosting all over the top and sides. Pipe any leftover frosting on top. (I used Ateco #30 tip.) Decorate with chocolate sprinkles or mini chocolate chips if desired. Slice and serve.

Step 5

Cover any leftover cake and store at room temperature for 2-3 days or in the refrigerator for up to 5 days.