Preheat the oven to 375. Combine the flour, baking powder, cinnamon, and salt in a bowl. In a larger bowl, combine the apple sauce, brown sugar, milk, oil, and maple syrup. Mix until it is well combined.
Add the dry ingredients into the wet ingredients and mix until just combined, until there are no clumps remaining. Don't over mix here!
Pour the batter into a large ziplock bag (or piping bag) and cut a hole in the corner. Pipe the batter into a greased mini donut pan.
Bake the donuts for 8-10 minutes, until you poke the top and it doesn’t jiggle. (i used a mini donut pan, so if your pan is regular sized, they will need a longer cook time)
While the donuts are baking, make the icing. Combine all three ingredients in a bowl and whisk until the icing is smooth, with no clumps. Dip the donuts in and enjoy!