Preheat oven to 375 degrees F. Spray muffin tin with non-stick cooking spray.
In a medium bowl stir together flour, baking powder, baking soda, cinnamon and salt.
With an electric mixer, mix together mashed banana, egg, sugar, butter and vanilla. Slowly add in dry ingredients.
Spoon mixture into muffin tins filling about each tin about 1/2 way.
In a small bowl add flour, cinnamon, brown sugar and butter for the topping. Use a fork to mix together until it forms into crumbles. Sprinkle on top of each muffin.
Bake for 15 minutes. Let the muffins cool in tin for 10 minutes before removing and place on wire cooking rack.