Makes 8 muffins
1 1/2 cups all-purpose flour
1 teaspoon baking powder
1 teaspoon baking soda
1/2 teaspoon salt
3 large bananas, mashed
1/2 cup white sugar
1/3 cup butter, melted
Preheat oven to 350 degrees F (175 degrees C).
Use paper liners and place in muffin tray.
Sift together the flour, baking powder, baking soda, and salt; set aside.
Combine bananas, sugar, egg, and melted butter in a large bowl.
Fold in flour mixture, and mix until just incorporated. Do not overmix.
Scoop into muffin pans.
Bake in preheated oven for 25 to 30 minutes.
It is done when a skewer inserted comes out clean.
More pictures here if you need step-by-step how-tos http://makingitdelicious.com/easy-banana-muffins/