For the cupcakes

1. Preheat the oven to 350 F. Line a 12-cup cupcake tin with paper cupcake liners.
2. In a medium bowl, sift together the flour, baking powder, baking soda and salt. Set aside.
3. In a large bowl, add the butter and granulated sugar. Beat with a handheld mixer or in your stand mixer until light and fluffy; about two minutes. Add the sour cream and vanilla. Slowly beat in the eggs, one at a time.
4. Incorporate the dry mixture and wet mixture together until thoroughly combined. Add the bananas and mix until just combined, being careful not to overmix.
5. Using an ice cream scoop, fill each cupcake liner three-quarters of the way full. Bake in the oven until the tops turn golden brown and a toothpick inserted in the middle of the cupcake comes out clean, 18 to 20 minutes. Remove the cupcakes from the oven to a wire rack and let cool before frosting.

For the frosting

1. Click the link above for the recipe.