Banana Muffins

Gather all ingredients. Preheat the oven to 350 degrees F (175 degrees C). Grease a 12-cup muffin tin or line cups with paper liners.
Sift flour, baking powder, baking soda, and salt together in a bowl; set aside.
Mix bananas, sugar, egg, and melted butter in a separate large bowl until well combined; fold in flour mixture until smooth.
Spoon batter into the prepared muffin cups, filling each ⅔ full.
Bake in the preheated oven until tops spring back when lightly pressed, about 25 to 30 minutes.
Cool briefly in the tin, then transfer to a wire rack to cool completely.