Preparation
Preheate oven to 375 degrees. Lightly grease 10 muffin cups or line with muffin papers. In large bowl, mix together flour, baking soda, baking powder and salt. In another bowl, beat together bananas, sugar, egg and melted butter. Stir the banana mixture into the flour mixture just until moistened. Spoon batter into prepared muffin cups. In a small bowl, mix together brown sugar, 2 tablespoons flour and cinamon. Cut in butter until mixture resembles coarse cornmeal. Sprinkle topping over muffins. Bake for 18-20 minutes until a toothpick inserted into center comes out clean.