1. Whisk together the flour, cream of tartar, baking soda, and salt in a large bowl until well combined.
2. Cream the softened butter, granulated sugar, and vanilla extract in another bowl until the mixture is light and fluffy.
3. Add eggs one at a time to the butter mixture, beating well after each addition until fully incorporated.
4. Gradually add the dry ingredients to the wet mixture, stirring only until just combined to prevent overmixing.
5. Cover the dough with plastic wrap and chill for at least 30 minutes in the refrigerator to help maintain the cookie shape during baking.
6. Preheat your oven to 350°F (or 400°F for a slightly crisper exterior).
7. Mix ground cinnamon and additional granulated sugar in a small bowl to prepare the coating.
8. Shape dough into small balls and roll them thoroughly in the cinnamon-sugar mixture for a complete coat.
9. Place the coated dough balls on parchment-lined baking sheets, ensuring they are spaced to avoid sticking during baking.
10. Bake the cookies for approximately 6-11 minutes, watching closely to prevent overbaking.
11. Allow the cookies to cool on the baking sheets so they can firm up, then transfer them to a cooling rack.