Preheat oven to 350ºF. Line baking sheets with parchment paper.
In the bowl of an electric mixer, beat the butter and granulated sugar until well combined and fluffy, about 2 minutes. Beat in the egg, mashed banana and vanilla extract until combined.
Mix flour, baking powder, salt and baking soda and gradually add to the creamed mixture. Stir in the chocolate chips.
Scoop the dough onto the prepared baking sheets. Bake 10-14 minutes, or until the edges are lightly browned.
Cool for 5 minutes before removing to wire racks to cool completely.
Recipe: This recipe is from Lil Luna. I didn't make any changes and it came out perfect.Storage: They will typically stay fresh in a sealed container for 3-4 days but can last up to a week when stored with a piece of sliced bread.Substitutes: For best results, follow the recipe as is. However if you have any questions for substitutions, please let me know!Nutritional Data: Please note that the nutrition label provided is an estimate only. It will vary based on the specific ingredients used. This nutrition label assumes that the batter is for 24 cookies.