- 1 1/4 cups all purpose flour
- 1 1/2 teaspoons baking powder
- 1/2 teaspoon baking soda
- 1/4 teaspoon salt
- 2 very ripe large bananas, peeled
- 1/2 cup sour cream
- 1 1/2 teaspoons vanilla extract
- 3/4 cup sugar
- 1/2 cup (1 stick) unsalted butter, room temperature
- 1 large egg
- 1 large egg yolk
- 1 1/2 cups powdered sugar
- 1 8-ounce package cream cheese, room temperature
- 1/2 cup (1 stick) unsalted butter, room temperature
- 1/2 cup smooth peanut butter (do not use old-fashioned or freshly ground)
- Chopped lightly salted roasted peanuts (optional)
- Preheat to 350°F and line 12 standard muffin cups with paper liners.
- Mash bananas with fork until smooth. Mix in the sour cream and vanilla.
- In another bowl, beat sugar and butter until light and fluffy. Add egg and egg yolk and beat until well blended. Add the dry ingredients to the wet ingredients (flour, baking powder, baking soda, and salt) until incorporated.
- Divide batter among prepared muffin cups (generous 1/4 cup for each).
- Bake cupcakes until toothpick comes out clean, about 20 minutes. Transfer cupcakes to rack and cool completely.
- Sift powdered sugar into large bowl. Add cream cheese, butter, and peanut butter. Beat mixture until smooth. Spread frosting over top of cupcakes and enjoy!