01 -
Preheat oven to 425°F (218°C). Spray a 12-count muffin pan with nonstick spray or use cupcake liners.
02 -
Whisk the flour, baking powder, baking soda, salt, cinnamon, and nutmeg together in a medium bowl. Set aside. In a large bowl or stand mixer, mash the bananas. On medium speed, beat or whisk in the melted butter, brown sugar, egg, vanilla extract, and milk.
03 -
Pour the dry ingredients into the wet ingredients, then beat or whisk until combined. If adding nuts or chocolate chips, fold them in now. Batter will be thick.
04 -
Spoon the batter into liners, filling them all the way to the top. Bake for 5 minutes at 425°F, then reduce to 350°F (177°C) and bake for an additional 16-18 minutes or until a toothpick inserted in the center comes out clean.
05 -
Allow the muffins to cool for 5 minutes in the muffin pan, then transfer to a wire cooling rack to continue cooling.