Preheat oven to 375°F. Set aside a lined baking sheet for the cookies.
Mix together cinnamon/sugar coating in a shallow bowl and set aside.
Cream together coconut oil and sugar. Add persimmon puree and vanilla extract and gently combine.
In a separate bowl, mix together oat flour, cream of tartar, baking soda, and salt. Add to wet ingredients and mix until a cookie dough forms. Add a splash of plant milk if the batter is too dry.
Scoop cookie dough into balls (about 1 tbsp in size) and roll in cinnamon sugar mixture. Place on baking sheet and flatten slightly into discs.
Bake 10 minutes, until browned and firm around the edges. (The center will still be soft but will firm up as it cools.) Leave on the baking sheet for about 5 minutes, then transfer to a cooling rack. Let cookies cool completely before eating for best results.
*Use certified gluten-free oat flour if gluten is an issue for you.