Step 1

Preheat the oven to 375° and line a baking sheet with parchment paper.

Step 2

In a medium sized bowl whisk together the flour, cream of tartar, baking soda and salt. Set aside.

Step 3

In another medium bowl beat the butter and sugar together until pale and fluffy, about 4-5 minutes. Add in the eggs and vanilla and beat for another 2 minutes. Be sure to scrape down the sides of the bowl to make sure everything is well combined.

Step 4

Add the dry ingredients in to the wet and mix until fully combined. Cover the bowl with plastic wrap and chill for 30 minutes.

Step 5

While the dough chills, combine the sugar and cinnamon in a small bowl.

Step 6

Form the dough into equal sized balls, about 1 inch and roll in the cinnamon sugar and coat evenly. Place the coated balls on the baking sheet keeping about 2 inches between them. Bake for 10 minutes. The cookies will look quite underbaked, but that's how they should look! Allow to cool for a few minutes on the pan before transferring to a cooling rack.