Heat the oven to 375 degrees F. Grease a 24-cup mini muffin tin well, including the flat top of the pan.
Whisk together the banana, applesauce, egg, maple syrup, melted butter, and vanilla.
Stir in the cinnamon, baking soda, baking powder, and salt.
Add the flour and stir just until no dry streaks remain, being careful not to overmix.
Fill each cup nearly to the rim. Sprinkle with the turbinado sugar and cinnamon, pressing lightly so it sticks.
Bake for 11 to 13 minutes, checking at 11. The tops should spring back when pressed.
Cool for 5 minutes in the tin, then twist each one out.