In a medium bowl, whisk together the flour, cornstarch, baking soda, cream of tartar, cinnamon, and salt. Set aside.
In a large mixing bowl, combine the avocado oil, sweetener, applesauce, and vanilla. Beat for 1-2 minutes until the mixture is smooth and well blended.
Gradually stir in the flour mixture until a thick, soft dough forms. If the dough feels too stiff, add 1-2 tablespoons of non-dairy milk to soften it.
Cover the dough and refrigerate for at least 30 minutes. Chilling the dough helps reduce spreading during baking. If you prefer a thinner cookie with a crackled top, chill for less time.
Assemble and Bake
In a small bowl, mix the cinnamon and sweetener for the coating until evenly blended.
Preheat your oven to 375°F and line your baking sheets with parchment paper.
Scoop heaping tablespoons of dough and roll them into balls.
Roll each dough ball in the cinnamon-sugar mixture until fully coated, then place them on the lined baking sheets, leaving about 2 inches between each cookie.
Bake the cookies for 9-11 minutes, until they are firm and slightly golden around the edges.
Once baked, remove the tray from the oven and gently tap it on the counter to help the cookies settle.
Let the cookies cool on the baking sheet for at least 10 minutes before transferring them to a cooling rack.
Notes
*If using a homemade apple sauce, add 1-2 tbsp/15-30ml non-dairy milk or water to thin the consistency.