Preheat oven to 375 degrees F. Line a baking sheet with Silpat or parchment paper, or lightly grease with oil.

In a mixing bowl, combine the flour, cream of tartar, baking soda, and salt. Set aside.

In a medium-sized mixing bowl, using a spoon, mix together the sugar and butter until creamy, about 2  minutes. This can also be done with a stand-alone mixer or hand blender (I usually just use a bowl and spoon). Then add the vanilla and applesauce, mix to combine. Add flour mixture and stir just until flour is incorporated. The dough should be firm and thick. If the dough is too soft, chill it in the refrigerator for 15 minutes to 1 hour until it stiffens a bit. This will help keep them from spreading too much.

In a small bowl, combine the sugar and cinnamon for rolling. Roll dough into about 1 inch balls. To keep them uniform, use either a 1 tablespoon measuring spoon or 1 tablespoon scooper.

Place cinnamon-sugar rolled balls on a prepared baking sheet, leaving about 2 inches between balls. Bake in the center of the oven for 8 – 9 minutes. For a little crispier cookie, bake for 10 minutes.

Let cool for a few minutes on the pan, they may be too soft just from the oven to move to a wire rack. Once cooled, enjoy!

Makes about 28 cookies

Store cookies covered on the counter for up to 3 days. Keep them fresher longer by storing them in the refrigerator for up 10 days. Freeze leftovers for up to 2 months (let thaw before eating).