Preheat your oven to 375 degrees. Get your muffin pan ready either by using muffin liners or by greasing the pan.
In a large bowl mix your flour, baking soda, baking powder, and salt. In a smaller bowl mix together your bananas, sugar, egg, pumpkin spice and butter.
Next pour your banana mixture into your flour mixture, mix lightly until the everything is combined.
Spoon your muffin mixture into your prepared muffin pans.
In a small bowl mix together the brown sugar, flour and pumpkin spice for your streusel topping. Once the ingredients are mixed together, cut in the butter until it’s nice and coarse.
Sprinkle the streusel on top of your pumpkin spice banana muffins.
Bake for 17 to 20 minutes or until a toothpick comes out clean.