Whisk the flour, baking powder and salt in a bowl.
In a separate bowl whisk the egg and sugar until it lightens and becomes a little fluffy.
Stir in the mashed bananas, buttermilk, butter, vegetable oil and banana extract.
Add the wet ingredients to the dry and stir. They do not need to be thoroughly combined; some lumpiness is desirable.
Spray a standard 12-muffin pan with vegetable spray. Fill the muffin pan with the batter. Do not fill to the brim.