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Best Banana Cake with Chocolate Buttercream Icing
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4.45 from 40 votes

Best Banana Cake with Chocolate Icing Recipe

This is the best banana cake we've ever eaten! The chocolate buttercream icing is perfect with this cake. Super moist and scrumptious - a real winner!
Prep Time30 mins
Cook Time1 hr
Total Time2 hrs 20 mins
Course: Dessert
Cuisine: American
Servings (change as needed): 15 generous servings
Author: Cheryl


  • 1 1/2 cups overripe bananas (for a strong banana flavor) (about 3 large bananas)
  • 2 teaspoons lemon juice
  • 1 1/2 cups buttermilk (or add 1 tablespoon lemon to milk to make 1 1/2 cups)
  • 3 cups all purpose flour
  • 1 1/2 teaspoons baking soda
  • 1/4 teaspoon salt
  • 3/4 cup unsalted butter, softened at room temperature (1 1/2 sticks)
  • 2 cups white sugar or brown sugar (or a bit less)
  • 3 eggs
  • 2 teaspoon vanilla extract

Chocolate buttercream frosting, Note 2

  • 1/2 cup softened butter (1 stick)
  • 1 3/4 cup icing sugar sugar also called confectioners' or powdered sugar
  • 1/3 cup cocoa powder
  • 1 teaspoon vanilla
  • 1-2 tablespoons milk


  • Preheat oven to 275F/135C. Grease (or spray with oil) and flour a 9 x 13 inch pan (22 x 33 cm).
  • PREPARE BANANAS: In a small bowl, mash bananas with a fork, mix with 2 teaspoons lemon juice and set aside.
  • PREPARE BUTTERMILK: Measure out the buttermilk (or milk plus lemon) in a medium bowl or measuring cup. Set aside.
  • PREPARE DRY INGREDIENTS: In a separate bowl, stir together flour, baking soda and salt. Set aside.
  • MAKE BATTER: In a large bowl, cream butter and sugar until fluffy with an electric mixer. Beat in eggs and vanilla. Alternate adding flour mixture and buttermilk a bit at a time - and beat until smooth. Stir in banana mixture. Pour batter into prepared pan.
  • BAKE AND FREEZE: Bake the cake for 1 hour or just until a toothpick comes out clean. As ovens vary, start checking after 55 minutes. Remove cake from oven and place it directly in the freezer, uncovered, on a tea towel for 45 minutes. This apparently makes the cake very moist - and it works!
  • MAKE FROSTING: Using a food processor: Add all buttercream/frosting ingredients into the processor and process until smooth, about 2 minutes. If too dry, add a small amount of extra milk (1 tablespoon) or, if too thin, add a bit more icing sugar - until you get the consistency you want. (Alternatively, use an electric or hand mixer and a mixing bowl - beating butter first, adding icing sugar and cocoa next, then vanilla and milk.) When the cake is fully cooled, frost the cake.


  1. Baking pans
    • Instead of a 9 x 13 inch (22 x 33 cm) pan, use two 8 x 8 inch (20 x 20 cm) pans or two 9 x 9 inch (22 x 22 cm) pans for a two-layer cake. You may need to lower the baking time a touch with the 9 inch pans.
  2. Cream cheese frosting
  3. Make Ahead:
    • This cake will keep in the fridge for 4-5 days, covered in plastic wrap or in an airtight container.
    • It also freezes very well for 2 months.
Nutrition values are estimates for generous portions with chocolate buttercream frosting.
Calories: 440kcal | Carbohydrates: 67g | Protein: 5g | Fat: 18g | Saturated Fat: 11g | Cholesterol: 76mg | Sodium: 340mg | Potassium: 184mg | Fiber: 2g | Sugar: 45g | Vitamin A: 574IU | Vitamin C: 2mg | Calcium: 46mg | Iron: 2mg