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+ servings
chocolate banana cake with slices taken out of it sitting on a cake stand

Chocolate Banana Cake

This chocolate banana marble cake is delicious and a lot easier to make than it looks.

Course Dessert
Cuisine American
Prep Time 25 minutes
Cook Time 30 minutes
Cooling Time 2 hours
Total Time 2 hours 55 minutes
Servings 10
Author Kelsie


Cake layers

  • 2 cups granulated sugar
  • 3/4 cup unsalted butter at room temperature
  • 3 large eggs
  • 1 1/2 cups mashed very ripe banana from 3 to 4 bananas
  • 1 1/2 teaspoons vanilla extract
  • 1 1/2 teaspoons baking powder
  • 1 1/2 teaspoons baking soda
  • 3/4 teaspoon salt
  • 3 cups all-purpose flour
  • 1 cup buttermilk
  • 1/2 cup semi-sweet chocolate chips

Chocolate frosting

  • 1 1/2 cups unsalted butter at room temperature
  • 2/3 cup unsweetened cocoa powder
  • 4 to 4 1/2 cups powdered sugar
  • 3 to 4 tablespoons whole milk or heavy cream
  • 1 teaspoon vanilla extract
  • 1/2 teaspoon espresso powder optional
  • 1/2 teaspoon salt


Cake layers

  1. Preheat the oven to 350 degrees. Spray 3 8-inch round cake pans with cooking spray. Line the bottom of the pans with parchment paper and spray the paper with cooking spray. Set pans aside.
  2. Combine the sugar and butter in a large mixing bowl and beat with an electric mixer on medium speed for 3 minutes, until very light and creamy. Beat in the eggs 1 at a time, beating for 30 seconds after each addition.
  3. Beat in the bananas, vanilla, baking powder, baking soda, and salt until well combined.
  4. With mixer on low speed, mix in one third of the flour followed by half of the buttermilk. Stop mixer and scrape the sides and bottom of the bowl with a rubber spatula. Mix in half of the remaining flour followed by the remaining buttermilk. Again scrape down the bowl. Add the rest of the flour and beat until batter is smooth.
  5. Transfer 1 1/4 cup of the cake batter to a small mixing bowl. Place the chocolate chips in a heat-proof bowl and melt in 20-second intervals, stirring after each interval, until chocolate is melted and smooth.*  Stir into the reserved 1 1/4 cups of batter.

  6. Divide about half of the remaining banana batter between the prepared cake pans. Dollop the chocolate batter over the top, then top with the remaining banana batter. Use a butter knife or the handle of a wooden spoon to swirl the two batters together—don’t over-swirl!
  7. If necessary, gently smooth the top of the batter with a small offset spatula. Bake cake layers for 29 to 35 minutes, until a cake tester inserted into the center of the cake layers comes out clean; try to avoid sticking the cake tester into the chocolate cake.
  8. Cool layers in pans for 20 minutes, then run a knife around the edges of the pans and carefully invert the cake layers onto wire racks to cool completely.

Chocolate frosting

  1. Place the butter in a large mixing bowl and beat with an electric mixer set to medium speed until very smooth and creamy. Turn mixer to low and beat in cocoa powder, then gradually beat in 4 cups of powdered sugar. Beat 1 to 2 minutes more.
  2. Add 3 tablespoons of milk, vanilla, espresso powder (if using), and salt and beat to combine. Turn mixer to medium and beat until frosting is smooth. Add additional powdered sugar if frosting is too thin or additional milk if it is too thick.


  1. Use a long serrated knife to trim your cake layers if they’ve domed. Set 1 cake layer on a cake stand or cardboard cake circle and top with a layer of frosting. Top with another cake layer and more frosting, followed by the final cake layer.
  2. Frost the cake with the remaining frosting and decorate as desired. Serve.

Recipe Notes

  • *Melting your chocolate slowly keeps it from scorching.
  • I used a large open star tip to and chocolate jimmies to decorate my cake but banana slices and chocolate chips would also be fun.
  • Variations

    • Spread a layer of creamy peanut butter over the cake layers before frosting them
    • Add a few tablespoons of peanut butter to the frosting! (You might need to add additional powdered sugar if you do.)
    • Spread a thin layer of banana curd between the cake layers for an extra dose of banana flavor