Preheat oven to 375 degrees.

Grease 12 muffin cups or line with paper liners.

In a large bowl, mix together 1 1/2 cups flour, baking soda, baking powder and salt.

In a separate bowl, beat together bananas, sugar, egg, vanilla, cinnamon, nutmeg and melted butter.

Stir the banana mixture gently into the flour mixture just until moistened.

Spoon batter into prepared muffin cups.

In a small bowl, stir together brown sugar, 2 tbs flour and cinnamon.

Cut in 1 tbs butter until mixture resembles coarse cornmeal.

Sprinkle on top of muffins.

Bake for 14 to 16 minutes or until a toothpick inserted into center comes out clean.