A marble cake is the perfect dessert to bake when you can’t decide if you are in the mood for a chocolate cake or a vanilla one. Marble cakes can come in all different flavors, of course, but most of them involve a swirl of chocolate and vanilla cake batters. This delicious Banana Marble Cake is a moist bundt cake with swirls of chocolate-banana and vanilla-banana batter in it!
The batter starts out with plenty of ripe bananas. I used about 4 medium sized bananas, but 3 large ones will do the trick. You don’t need to be exact on the quantity of banana, so don’t worry if you end up with a couple of extra tablespoons in the mixing bowl because your bananas are on the larger side. The bananas are incorporated into a vanilla-scented buttermilk batter. Buttermilk always helps to create a tender, moist cake and this recipe is no exception to that rule.
Once the vanilla batter is prepared, 1 cup of it is transferred to a small bowl and combined with cocoa powder and a small amount of additional buttermilk. The extra buttermilk helps to ensure that the cocoa powder can be completely – and easily – incorporated into the banana base without making that layer of batter too thick or dry. Mini chocolate chips are also added into the mixture. Mini chocolate chips deliver a surprising amount of chocolate flavor in every bite, while remaining suspended in the batter. Larger chocolate chips can be used, but you may find that some of them sink during baking.
Half of the vanilla-banana batter is poured into a greased and floured bundt pan, then the chocolate batter is poured in before the remaining vanilla batter is added. The two batters should be gently swirled together with a butter knife before the cake goes into the oven. Swirl very gently if you prefer big patches of chocolate and vanilla, or a little more creatively if you prefer a more uniform swirliness!
The cake is ready to eat as soon as it has cooled. It is delicious on its own and can make a fantastic dish for brunch or for dessert. If you want to dress it up, a drizzle of cream cheese icing is the perfect accompaniment. The cake will keep well for a few days after baking, when stored in an airtight container.
Banana Marble Cake
1 cup mashed banana (3-4 medium)
2/3 cup vegetable oil
3 large eggs
1 tbsp vanilla extract
2 cups sugar
3 cups all purpose flour
2 tsp baking powder
1/2 tsp baking soda
1 tsp salt
1 cup buttermilk + 2 tbsp buttermilk, divided
1/4 cup unsweetened cocoa powder
1/2 cup mini chocolate chips
Preheat oven to 350F. Lightly grease and flour a 10-inch bundt pan.
In a large bowl, whisk together mashed banana, vegetable oil, eggs, vanilla extract and sugar until well-combined.
In a medium bowl, whisk together flour, baking powder, baking soda and salt.
Stir half of the flour mixture into the banana mixture, followed by 1 cup of the buttermilk. Stir in the remaining flour mixture and mix until no streaks of dry ingredients remain visible.
In a small bowl, whisk together 2 tbsp buttermilk and 1/4 cup unsweetened cocoa powder. Add in 1 cup of the banana cake batter and mix until completely combined. Stir in mini chocolate chips.
Pour half of the vanilla-banana batter into the prepared pan, followed by the chocolate-banana batter. Layer on remaining vanilla-banana batter and use a knife to gently swirl the two batters together.
Bake for about 50 minutes, until a toothpick inserted into the cake comes out clean or with only a few moist crumbs attached, and the top of the cake springs back when lightly pressed.
Allow cake to cool in the pan for at least 20 minutes, then turn out onto a wire rack to cool completely.
Makes 1 cake; serves 16