John Kanell - Chocolate Zucchini Cake

John Kanell - Chocolate Zucchini Cake
John Kanell turns Summer Zucchini into a fabulous chocolate cake.
Chocolate Zucchini Cake


  • 3 cups all-purpose flour 360g
  • 1 cup cocoa powder 100g, unsweetened natural
  • 1 tbsp baking soda 18g
  • 3/4 tsp baking powder 1g
  • 1 1/2 tsp espresso powder 1g, heaping, optional
  • 3/4 tsp salt 4g
  • 1 ½ cup vegetable oil 354ml
  • 1 1/2 cup granulated sugar 300g
  • 1 cup packed light brown sugar 200g
  • 6 large eggs at room temperature
  • 1/2 cup sour cream or plain yogurt 115g, at room temperature
  • 1 tbsp pure vanilla extract 15ml
  • 4 1/2 cups zucchini 475g, about 3 medium, shredded
  • 1 1/2 cup chocolate chips 265g, semi-sweet


  • 1 1/2 lb confectioner's sugar 680g
  • 1 1/2 cup unsalted butter 342g, room temperature
  • 4 1/2 tbsp heavy whipping cream 67ml
  • 1/3 cup cocoa powder 40g
  • 1 1/2 tsp vanilla 7ml, optional
  • 1 1/2 tsp espresso 7ml, optional


  • 3/4 cup semisweet chocolate 130g
  • 1/3 cup heavy cream 79ml


  • 1/2 cup chocolate. Semi-sweet, melted, cooled


For the Cake:

  1. Heat oven to 350 degrees.
  2. Spray 3, 8-inch cake pans with non-stick oil.
  3. Cut a parchment round for the bottom of each pan and place inside. I always use cake strips, which prevent my cake layers from doming. If you don’t have any on hand, you can make them with wet paper towels and tin foil!
  4. Mix together flour, cocoa powder, baking soda, baking powder, espresso powder (optional), and salt in a large bowl.
  5. Mix oil, granulated sugar, brown sugar, eggs, sour cream, and vanilla together in a second large bowl. If using a stand mixer add the wet ingredients into your bowl and mix together with a paddle attachment.
  6. Add the shredded zucchini to the wet mixture and mix on low to combine.
  7. Mix the wet bowl with dry bowl and beat together on medium. Add in chocolate chips.
  8. Pour mixture into pans. Cook 30-35 minutes, or until centers are springy.
  9. Use a toothpick to check to see if they’re finished. Let cakes cool in the pans on a wire rack. They must be cool before working with frosting and assembly.

For the Chocolate Buttercream:

  1. Whip the butter for about 5 minutes using a paddle attachment (in a stand-up mixer)
  2. Beat in the confectioner’s sugar slowly.
  3. Add the cream.
  4. Sift in the cocoa powder and mix until combined.
  5. You may add the optional vanilla and espresso at this step.
  6. Mix until you have a fluffy, even consistency.

For the Chocolate Shards:

  1. Pour 1/2 cup melted and cooled semi-sweet chocolate onto a sheet of parchment paper.
  2. Spread out onto parchment paper with offset spatula. Let cool completely.
  3. Break up into shards. Dust with cocoa powder.

For the Ganache:

  1. Melt the chocolate and cream in a microwave for a few 30 second bursts at 50% power.
  2. Mix together and transfer to a piping bag with and cut the tip off. Drizzle ganache over top and sides for a nice drip effect. Quickly use an offset spatula to spread out ganache on top.

For the Assembly:

  1. Pipe buttercream onto the first layer. Add second layer and repeat.
  2. Apply a thin coat of buttercream to the side and top then smooth.
  3. Pour ganache on top and use an offset spatula to spread. You can apply small drips to the side if desired.
  4. Top with chocolate shards.

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