Preheat your oven to 400℉ (200℃). Line two baking sheets with parchment paper.
In a medium bowl, combine the flour, cream of tartar, baking soda, and salt. Set aside.
In a large bowl, beat the softened butter until smooth and creamy.
Add the granulated and brown sugars to the butter. Beat until creamy and well blended.
Mix in the eggs and vanilla extract until you achieve a smooth dough consistency.
Gradually add the dry mix to the wet mixture, stirring until just combined. Avoid overmixing.
In a shallow bowl, mix the granulated sugar and cinnamon for rolling.
Roll one tablespoon of cookie dough into a ball and coat each ball in the cinnamon sugar mixture.
Place the coated dough balls on the prepared baking sheets, spacing them 2 inches apart.
Bake for 6 to 8 minutes until edges are set but centers are slightly soft.
Let cookies cool on the baking sheet for 2 minutes before transferring to a cooling rack.