In a medium mixing bowl, sift together the flour, baking powder, salt, cinnamon and nutmeg. Set aside.
In a large mixing bowl or stand mixer fitted with the paddle attachment, cream together the butter, sugar and light brown sugar. When blended, light and creamy, add the egg, vanilla and mashed banana.
Gradually add the dry mixture to wet until fully combined.
Cover the bowl with plastic wrap and refrigerate for a minimum of 2 hours.
After the dough has chilled, preheat the oven to 350°F.
In a small bowl, stir together the sugar and cinnamon.
With clean hands, roll the dough into 1 1/2 inch balls. Dough might be sticky and not roll well, have no fear, just plop it into the sugar and coat.
Place onto a parchment paper or silicone mat lined cookie sheet about 2 inches apart.
Bake for 13-15 minutes or until cookie tops start to crack. Do not wait until cookies brown, they will be overdone.
Allow the cookies to cool on cookie sheet for at least 5 minutes before carefully transferring to a cooling rack using a spatula.
If you've tried this recipe, please come back and leave a comment to let us know how it went and if you made any modifications!