Pour in the flour, ground cinnamon, baking powder, baking soda, and cream of tartar to the bowl. Mix until all of the dry ingredients are absorbed.
Use a rubber spatula to fold in the oats. Then, preheat the oven to 350°F and chill the cookie dough in the fridge for 30 minutes.
Scoop onto cookie sheet. Bake cookies for 10-12 minutes or until the outsides of the cookie turn golden brown.