Karen's Banana Crumb Muffins

1 1/2 cups all purpose flour
1 teaspoon baking soda
1 teaspoon baking powder
1/2 teaspoon salt
3 bananas, mashed
3/4 cup white sugar
1 egg, lightly beaten
1/3 cup butter, melted
1/3 cup brown sugar
2 tablespoons all purpose flour
1/8 teaspoon ground cinnamon
1 tablespoon butter

1. Preheat oven to 375 degrees. Lightly grease 10 muffin cups.
2. Mix together 1 1/2 cups flour, baking soda, baking powder, and salt. In another bowl, beat together bananas, sugar, egg and melted butter. Stir banana mixture into flour mixture just until well moistened. Spoon batter into muffin cups.
3. Mix together brown sugar, 2 tablespoons flour and cinnamon. Cut in 1 tablespoon butter until mixture resembles coarse cornmeal. Sprinle topping over muffins.
4. Bake in preheated oven for 18 to 20 minutes.