Overhead shot of Chocolate Zucchini Cake with Blackberry Buttercream on a board with blackberries and fresh thyme
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Chocolate Zucchini Cake with Hibiscus Buttercream

This recipe for Zucchini Chocolate cake is extremely moist and tender with tart hibiscus buttercream.

Course Dessert
Cuisine American
Keyword chocolate cake, chocolate zucchini cake, Chocolate Zucchini Cake with Blackberry Buttercream, chocolate zucchini cake with hibiscus icing
Prep Time 1 hour 30 minutes
Cook Time 30 minutes
cooling 1 hour
Total Time 1 hour
Servings 12 servings
Calories 564 kcal
Author Janet Barton

Ingredients

Chocolate Zucchini Cake

  • 2 1/2 cups all-purpose flour
  • 1/2 cup cocoa
  • 2 teaspoons baking soda
  • 1 teaspoon salt
  • 2 eggs
  • 2 cups sugar
  • 1 cup light flavored olive oil
  • 1/2 cup buttermilk
  • 2 teaspoons vanilla
  • 1/2 cup boiling water
  • 2 cups grated zucchini

Blackberry Swiss Meringue Buttercream

  • 2/3 cup 150 g egg whites
  • 1 1/4 cups 250 g sugar
  • 1 1/2 cups 340 g or 3 cubes unsalted butter, cut into 1 tbl. cubes or slices
  • Pinch of salt
  • 1/2 teaspoon vanilla
  • 2-4 tablespoons Blackberries puree and remove seeds.

Instructions

Chocolate Zucchini Cake

  1. Preheat oven to 350 degrees.  Grease and flour three 8-inch round cake pans.  Line with a parchment paper.  Set aside.  In a large bowl sift together flour, cocoa, baking soda, and salt.  Set aside.  In the bowl of a stand-up mixer beat eggs,  With the mixer running, slowly add sugar and mix until light yellow in color. Slowly add olive oil, buttermilk, and vanilla.  Mix until smooth and light in color.  Beat in flour and cocoa mixture until smooth.  Fold in grated zucchini then boiling water.  Pour batter into prepared baking sheet and place in the preheated oven.  Bake for 30 minutes or until cake springs back when lightly touched.  Remove from oven and cool for 5 minutes.  Invert cakes onto a cooling rack until completely cool OR for a moister cake immediately wrap in plastic and wrap and place right into a freezer.  Can be frozen for several days, or place in a refrigerator until completely cool before using.

Hibiscus Swiss Meringue Buttercream

  1. In a very clean bowl of an electric mixer, add egg whites and sugar.  Place over a simmering pot of water, stirring constantly until temperature reaches 160 degrees F.  Rub a small amount of the mixture between two fingers to make sure the sugar is dissolved.  Remove from heat.  Using the whisk attachment, beat until the mixture is a thick meringue and the bottom of the bowl is cool to the touch. The bowl must be cool before adding the butter. Replace the whisk with the paddle attachment.  With the mixture on medium-low speed add butter once slice at a time until all of the butter has been incorporated.  The mixture should be silky smooth and thick.  The mixture may begin to look curdled, keep mixing until it is smooth.  This can take 10 minutes or so.  Mix in salt and vanilla.  

  2. Replace the whisk with the paddle attachment.  With the mixture on medium-low speed add butter one slice at a time until all of the butter has been incorporated.  The mixture should be silky smooth and thick.  The mixture may begin to look curdled, keep mixing until it is smooth.  This can take 10 minutes or so.  Mix in salt and vanilla.  Add blackberry puree, if using. Once the puree is added keep mixing until the mixture is silky again.

Recipe Notes

Nutrition Facts
Chocolate Zucchini Cake with Hibiscus Buttercream
Amount Per Serving (12 servings)
Calories 564 Calories from Fat 234
% Daily Value*
Fat 26g40%
Saturated Fat 15g75%
Cholesterol 89mg30%
Sodium 625mg26%
Potassium 200mg6%
Carbohydrates 78g26%
Fiber 2g8%
Sugar 55g61%
Protein 6g12%
Vitamin A 820IU16%
Vitamin C 5.3mg6%
Calcium 37mg4%
Iron 2mg11%
* Percent Daily Values are based on a 2000 calorie diet.