Preheat the oven to 350℉. Grease the muffin tin(s) with non-stick spray or line with muffin liners.

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

Add the flour, baking powder, baking soda, and salt and mix at low speed just until incorporated. Fold in the chocolate chips.

Scoop the batter into the prepared muffin tin(s), filling each cup (18 in total) about ¾ full with batter. Bake in the preheated oven for 25-30 minutes or until a toothpick inserted into the center comes out clean. Let cool in the muffin tin for 10 minutes before transferring to a wire rack to finish cooling. Enjoy!