Pre-heat the oven to 350°F.
Grease a 12-cup muffin tin or line cups with paper liners.
In a medium bowl, sift flour, baking powder, baking soda and salt; stir to thoroughly combine; set aside.
In a separate medium bowl, add bananas, sugar, the egg, vanilla extract and melted butter; mix well to combine; fold in flour; stir until mixture is smooth.
Spoon batter into the prepared muffin cups; filing each 2/3 full.
Place in the pre-heated oven and bake until tops spring back when lightly pressed; about 25 to 30 minutes.
Remove from the oven; place on a cooling rack for 15 minutes to cool completely.
Remove muffins from tin; place paper towel in the bottom of an air tight container; place muffins on top of the paper towel; cover the top with another piece of paper towel; cover and store at room temperature; will keep for 3 – 4 days; if not eating within that time period, follow same process and freeze.
