Mix together cinnamon sugar coating in a shallow bowl and set aside.
Cream together coconut oil and sugar until smooth. Add milk (make sure it's room temperature) and vanilla extract and mix to combine.
Mix in flour, cream of tartar, baking soda, and salt until a thick and smooth dough forms. Cover and chill in the fridge for 10 minutes.
Scoop cookie dough into 12 balls. Take one ball and divide it in half. Flatten each half into discs about ¼" thick.
Place 1 heaped tbsp of stewed apples in the center of one of the discs. Top with the other disc and seal the edges. Gently roll into a ball and place on a lined baking sheet.
Repeat with remaining cookie dough. Place the baking sheet in the fridge for 10 minutes.
Preheat oven to 375°F.
Take baking sheet out of fridge. Roll the cookie dough balls in the cinnamon sugar mixture. Place back on the baking sheet and slightly flatten into discs. Leave about 2 inches of space between each cookie.
Bake 11 minutes, until lightly golden 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 2 minutes, then transfer to a cooling rack.
Let cookies cool completely before eating for best results. Store leftovers in an air-tight container in the fridge.
Notes
1) It should be the consistency of softened butter. I find room temperature coconut oil works well. Use refined coconut oil so it doesn't leave a coconut-y flavor.2) Replace all purpose flour with the same amount (in grams) of oat flour. You will also need to add ground flaxseed with the milk to help the cookies hold together. Mix 4 tsp of ground flax with the 4 tbsp of milk called for in the recipe. Let this gel for a few minutes before mixing with the wet ingredients. Or you can try an all purpose gluten-free flour blend.