Marbled Banana Bundt Cake

marbled banana bundt cake on cake stand

A delicious cake with swirls of chocolate banana mixed into plain banana batter. It’s dense and moist and very delicious


  • 3 cups all purpose flour
  • 2 tsp baking soda
  • 1/2 tsp salt
  • 2 sticks (8 ounces) unsalted butter, at room temperature
  • 2 cups sugar
  • 2 TBS cocoa powder
  • 2 tsp pure vanilla extract
  • 2 large eggs, at room temperature (I used duck eggs)
  • 4 very ripe bananas (about 1 1/21 3/4 cups mushy banana)*
  • 1 cup sour cream

*I used thawed, frozen bananas and it worked just fine


  • Center a rack in your oven and preheat to 350
  • Butter and flour a 12 cup bundt pan (very important to get this step right)
  • In a medium bowl whisk together the flour, baking soda and salt
  • In a stand mixer with the paddle attached, beat the butter until creamy.  Add the sugar and beat on medium speed until light and fluffy.
  • Beat in the vanilla
  • Add the eggs, one at a time until well incorporated.
  • Lower the speed to low and mix in the banana.
  • Turn off the mixer and half the dry ingredients but for the cocoa powder. Mix on low until combined. Add the sour cream, mix in, then add the rest of the dry ingredients
  • Remove 1 1/2 cups of batter and place in a medium bowl. Stir in the cocoa powder.
  • Pour the plain batter into the prepared bundt pan.
  • Drop the chocolate batter by large dollops on top of the plain batter. Swirl in with a butter knife (see video)
  • Tap the pan on a table a couple of times to settle the batter.
  • Bake in the preheated oven until a tester comes out clean – 65 to 75 minutes (mine took a little big longer, about 7 more minutes)
  • Cool on a wire rack, then remove from pan.
  • Dust with powdered sugar if desired before serving.

Keywords: banana cake, bundt cake, chocolate banana cake