Step 1

Preheat oven to 375 degrees F. Lightly grease 12 muffin cups, or line with muffin papers.

Step 2

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

Step 3

In another large bowl, beat together bananas, sugars, egg, oil and vanilla. Stir the banana mixture into the flour mixture just until moistened. Evenly scoop batter into prepared muffin cups.

Step 4

Make the Crumb Topping: In a small bowl, mix together brown sugar, flour and cinnamon. Cut in butter until evenly distributed and crumbly in texture. Sprinkle topping over muffins.

Step 5

Bake in preheated oven for 18 to 20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.