Preheat oven to 375deg

Lightly grease muffin pan or place liners

Muffin mixture In a large bowl, mix flour, baking soda, baking powder, and salt

In a seperate bowl, beat bananas, white sugar, melted butter, and egg

Combine both mixtures

Spoon the batter into the muffin pan until about 3/4 full per muffin

Crumb topping. Mix brown sugar, for, and cinnamon together in a small bowl

Using a fork, mix in one tablespoon of butter until mixture is crumbly

Sprinkle over the top of the muffins

Bake at 375 for 18-20 minutes or until a toothpick in the center comes out clean