Yummy Banana Crumble 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 flour
1 egg, lightly beaten
1/3 cup oil
1 teaspoon vanilla
Dash of cinnamon and nutmeg
1/3 cup packed brown sugar
2 Tablespoons all-purpose flour
1/8 teaspoon ground cinnamon
1 Tablespoon butter

1.Preheat oven to 375 degrees F. Lightly grease muffin cups,or line with muffin papers.
2.In a large bowl, 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 the banana mixture into the flour mixture just until moistened. Spoon batter into prepared muffin cups.
3.In a small bowl, mix together brown sugar, 2 Tablespoons flour and cinnamon. Cut in 1 Tablespoon butter until mixture resembles coarse cornmeal. Sprinkle topping over muffins.
4.Bake in preheated oven for 18 to 20 minutes, until toothpick inserted into center of a muffin comes out clean.