- 1 cup cake flour (not self-rising), plus more for pan
- 1/2 teaspoon baking soda
- 1/4 teaspoon baking powder
- 1/4 teaspoon salt
- 1/8 teaspoon ground cinnamon
- Ground cloves
- 2 very ripe bananas, 1 mashed (1/2 cup), 1 very finely chopped (1/2 cup)
- 1/4 cup buttermilk
- 1/2 teaspoon pure vanilla extract
- 2 ounces (4 tablespoons) unsalted butter, softened, plus more for pan
- 1/2 cup dark-brown sugar
- 1 large egg
Preheat oven to 350 degrees. Butter a 9-inch round cake pan. Line with parchment cut to fit, and butter and flour parchment. Sift flour, baking soda, baking powder, salt, cinnamon, and a pinch of cloves into a medium bowl. Whisk mashed banana, buttermilk, and vanilla in a small bowl.
Beat butter and sugar with a mixer on medium speed until smooth. Add egg, and beat until well combined. Reduce speed to low, and add flour mixture in 2 additions, alternating with banana mixture. Add chopped banana, and beat until well combined. Pour batter into pan, and use a spatula to spread into an even layer.
Bake until golden brown and a tester inserted in the center comes out clean, about 20 minutes. Let cake cool in pan on a wire rack for 10 minutes. Run a knife around edge of pan, and invert pan onto rack. Remove parchment, and flip cake so top side faces up. Let cool completely on wire rack.