Preheat the oven to 375°F (190°C). Lightly grease 10 muffin cups or line them with muffin papers.
In a large bowl, mix together 1 1/2 cups of flour, baking soda, baking powder, and salt. In another bowl, beat together the bananas, sugar, egg, and melted butter. Stir the banana mixture into the flour mixture just until moistened. Spoon the batter into the prepared muffin cups.
In a small bowl, mix together brown sugar, 2 tablespoons of flour, and cinnamon. Cut in 1 tablespoon of butter until the mixture resembles coarse cornmeal. Sprinkle the topping over the muffins.
Bake in the preheated oven for 18 to 20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Let cool for 10 minutes before serving.