Preheat the oven to 400℉. Line 12-count cupcake tin(s) with cupcake liners.

In a large bowl using an electric handheld mixer, cream the softened butter and sugar on medium speed for 1 minute. Add the eggs, vanilla, and mashed bananas and continue beating for 30 seconds until fluffy.

In another smaller bowl, whisk together the flour, baking powder, and baking soda. Add into the wet ingredients and mix on low just until incorporated.

Scoop the batter into the lined cupcake tin(s), filling each cup ¾ full. Bake in a 400℉ oven for 5 minutes, then lower the temperature to 350℉ and continue baking for another 12-15 minutes or until a toothpick inserted into the center of each cupcake comes out clean. Let cool in the tin for 10 minutes before transferring to a wire rack to finish cooling completely before icing. Bake the remaining cupcakes.

In a heat-safe bowl, melt the butter and chocolate chips together in the microwave in 20-second increments, stirring between each increment until fully melted. Cover and refrigerate for 30 minutes or until solid.

Using an electric mixer on high speed, cream the chilled butter/chocolate mixture until fluffy. Add the cocoa and powdered sugar and mix on low until incorporated, then add the milk starting with 1 tablespoon and increase the speed to high and whip until fluffy, adding milk until desired consistency is reached. Frost the completely cooled cupcakes using a piping bag fitted with your desired tip. Enjoy!