Chocolate Zucchini Cake

Chocolate Zucchini Cake

Chocolate Zucchini Cake

Recipe by PJ Hamel

King Arthur 2020 Recipe of the Year

When you've baked enough zucchini bread but the green vegetable is still finding its way into your kitchen, switch things up with this Chocolate Zucchini Cake. It uses three whole cups of zucchini, yet you'd never know there was anything but chocolate in this ultra-moist, rich, fudgy cake. The zucchini ensures a tender crumb — think banana bread meets carrot cake — while the cocoa powder and espresso create a robust chocolate flavor. This frosted cake is likely to become your new favorite way to eat zucchini. (You're welcome.)

The Chocolate Zucchini Cake was one of our Bake of the Week recipes for July 2022.

Prep
15 mins
Bake
40 to 45 mins
Total
1 hr
Yield
one 9" x 13" cake
Chocolate Zucchini Cake - select to zoom
Chocolate Zucchini Cake - select to zoom
Chocolate Zucchini Cake - select to zoom
Chocolate Zucchini Cake - select to zoom

Instructions

  1. Preheat the oven to 325°F. Lightly grease a 9" x 13" pan.

  2. To make the cake: In a large mixing bowl, beat together the butter, oil, sugar, vanilla, baking powder, baking soda, and salt until smooth.

  3. Beat in the eggs.

  4. Stir in the sour cream, buttermilk, or yogurt alternately with the flour. (See "tips," below for more details on this step, if needed.)

  5. Add the cocoa and espresso powder, mixing until smooth.

  6. Fold in the zucchini and chocolate chips. Spoon the batter into the prepared pan.

  7. Bake the cake for 40 to 45 minutes, until the top springs back lightly when touched, and it seems set. A toothpick or paring knife inserted into the center should come out clean when done.

  8. Remove the cake from the oven and cool in the pan on a wire rack. 

  9. To ice the cake: In the microwave or on the stovetop, combine the chocolate chips and half-and-half, heating until the chocolate softens. Stir to melt the chocolate, and spread over the completely cooled cake.

  10. Storage information: Store leftover cake, well covered, at room temperature for several days; freeze for longer storage.

Tips from our Bakers

  • Zucchini's weight varies a lot, depending on its moisture. To avoid having to make a decision about weight, consider measuring zucchini by volume.

  • What's the best way to alternately stir in the flour and wet ingredients? Start by adding about a third of the flour to the batter and mix gently until it's incorporated. Stir in about half of the sour cream, buttermilk, or yogurt. Add another third of the flour, the remaining sour cream, buttermilk, or yogurt, followed by the remaining flour, stirring briefly after each addition. This method of incorporating the ingredients prevents gluten formation and ensures a super tender cake. 

  • Don't worry about espresso powder giving this cake any coffee flavor; it's there strictly to enhance the cake's deep-dark chocolate taste, which it does admirably.

  • For a simpler icing, bake the cake for 30 to 35 minutes, until the top feels set. Sprinkle the hot cake with 1 cup (170g) chocolate chips, and return it to the oven for 5 minutes or until a toothpick or paring knife inserted into the center comes out clean. Remove the cake from the oven, and use an offset spatula or rubber spatula to spread the chocolate chips into a smooth glaze. Alternatively, simply dust the cooled cake with a light coating of confectioners' sugar or non-melting sugar.