Preheat the oven to 425°F and prepare a muffin pan with silicone or paper liners.
Make the streusel first by adding flour, brown sugar, sugar, cinnamon, pumpkin pie spice, and cubed cold butter into a medium bowl. Use a pastry cutter or a fork to combine everything and create a crumble. Place in the fridge until ready to use so the butter stays nice and cold.
Place the flour, baking soda, baking powder, pumpkin pie spice, and salt for the. muffins in another medium mixing bowl and mix together using a whisk or fork. Set aside.
Place the pumpkin puree, ripe banana, egg, sugar, and vanilla in a large mixing bowl and whisk to combine.
Pour half of the dry ingredients into the wet ingredients, and mix in with a spatula. Add the other half and continue to mix by hand until everything is combined.
Place the batter in the muffin pan evenly across 12 sections. The cups should be about ¾ full. Remove the streusel from the fridge and sprinkle it on top of each muffin.
Bake for 5 minutes at 425°F and then reduce the temperature to 350°F. Don't open the door, just reduce the heat. This step will help the muffins rise in the pan and bake evenly. Continue baking for 15-18 more minutes until a toothpick comes out clean.
While the muffins are baking, make the vanilla glaze. Place the powdered sugar, vanilla, and milk into a mixing bowl and stir with a fork to combine until smooth. Set aside.
Remove the muffins from the oven and let them cool in the pan for 5 minutes before placing them on a cooling rack to cool for another 5 minutes.
Drizzle the vanilla glaze on top of each muffin before serving. Enjoy!