Preheat oven to 400º.
Prepare donut tins by spraying well with cooking spray.
Set aside.
In a large mixing bowl, combine flour, sugar, baking powder, soda, salt and cinnamon.
Stir well and set aside.
In a separate microwaveable bowl, melt butter.
Add applesauce, buttermilk, vanilla and cinnamon chips.
Whisk well to combine.
Add wet mixture to dry mixture and stir just until moistened.
Transfer ingredients to a zip lock bag (without the “stand and fill” bottom).
Cut off a corner and pipe the donut dough into the donut tins a little over ¾ full.
Bake in preheated oven for about 9-10 minutes or until donuts test done with a toothpick.
Remove from oven and cool for 10 minutes.
Dip top of donuts in bowl with melted butter.
Sprinkle with Cinnamon-sugar mixture and pat down slightly.
Turn donut over and coat the bottom with melted butter.
Sprinkle cinnamon-sugar mixture over the bottom part of the donuts.
(I just used my fingers to do this).
Turn donut over.
Sprinkle the bottom of the donut with more cinnamon-sugar.
Do this a total of four times (for the top and four times for the bottom), until the mixture adheres well and the donuts are really well covered with the cinnamon-sugar mixture.
Place on wire racks to cool completely.