1. Preheat the oven to 375°F and line two baking sheets with parchment paper.

2. In a large bowl, beat the softened butter and granulated sugar until light and fluffy.

3. Add the eggs one at a time, then mix in the vanilla extract.

4. In a separate bowl, whisk together the flour, cream of tartar, baking soda, salt, and cinnamon.

5. Gradually mix the dry ingredients into the wet ingredients until a soft dough forms.

6. In a small bowl, stir together the sugar and cinnamon for rolling.

7. Scoop the dough into balls and roll each one in the cinnamon-sugar mixture.

8. Place the dough balls on the prepared baking sheets, leaving space between each one.

9. Bake for 8 to 10 minutes, until the edges are set and the centers still look slightly soft.

10. Let the cookies cool on the baking sheet for 5 minutes, then transfer them to a wire rack.