Preheat oven to 350°F. Grease or line a muffin tin with muffin liners.
Combine mashed banana, pumpkin, coconut oil and maple syrup in a large bowl. Whisk until smooth and well combined.
Add the flours, baking powder, salt and spices to the bowl.
Stir until well combined.
Scoop batter evenly into prepared muffin tin.
Bake for 25 minutes or until center is cooked through.
Remove from oven and let cool for 5 minutes in the tin.
Transfer the muffins to a cooling rack.
Brush the tops of the muffins with the melted coconut oil to prep them for the topping.
Combine the sugar and cinnamon in a small bowl and dip the muffin tops into the mixture. Alternatively, spoon the cinnamon sugar on top of each muffin.