Preheat the oven to 350 degrees F (180 degrees C).
Add the unsweetenend applesauce, milk, egg, oil, and maple syrup to a bowl and whisk until smooth.
To the same bowl, add in the flour, baking powder, and cinnamon and mix until smooth. Do not overmix.
Place 1 tablespoon of batter into the cups of a mini silicone muffin pan. If you are not using a silicone muffin pan, spray the mini muffin pan well before pouring in the batter.
Bake the mini donut muffins for 15 minutes and let them cool completely before removing them from the pan.
For an optional cinnamon coating, mix together the sugar and cinnamon until combined. Lightly brush the muffins with melted butter and dip them into the cinnamon sugar mixture to coat, shaking off any excess mixture.
