First, for the muffins: 1. Combine all dry ingredients (Flour, baking soda, baking powder, and salt) 2. In a seperate bowl, combine bananas, sugar, egg, butter, vanilla, cinnamon, and nutmeg 3. Add banana mixture to flour mixture and stir until moist 4. Gently fold in the blueberries 5. Spoon muffin batter into non-stick muffin pan about 2/3 of the way up the sides. You should have enough for 12 muffins. Now for the topping: Combine the flour, cinnamon, butter and sugar with a fork Sprinkle mixture over muffins Bake at 370 degrees F for 18-20 minutes until a toothpick comes out clean.