In a large mixing bowl, cream together butter and sugar until light and fluffy
Add eggs and vanilla and mix until combined
Fold in flour, cream of tartar, baking soda and salt until dough forms - dough will be slightly sticky
Using a medium cookie scoop, scoop out dough balls and roll in mixture of cinnamon and sugar until coated, place on baking sheet at least 2 inches apart!
Bake for 8-10 minutes
Remove from oven and make a well in the center of each cookie by pressing with a tablespoon
Add apple filling to center and bake another 2-3 minutes
Take out and let cool completely
Optional: drizzle with caramel or icing