Step 1

Preheat the oven to 350 degrees F. Line 2 large baking sheets with a Silpat baking mat or parchment paper and set aside.

Step 2

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

Step 3

In the bowl of a stand mixer, beat the butter and sugar together until light and creamy, about 2 minutes. Scrape down the sides of the bowl with a spatula, if necessary.

Step 4

Add the eggs and vanilla extract and beat until combined.

Step 5

Turn the mixer off and add all of the dry ingredients. Mix on low until just combined. Don't over mix.

Step 6

Roll the cookie dough into balls, about 2 tablespoons of dough per cookie.

Step 7

In a small bowl, combine the sugar and cinnamon. Roll all of the cookies into the cinnamon sugar mixture, making sure each cookie ball is generously coated.

Step 8

Place the cookie dough balls onto the prepared baking sheet, about 2 inches apart. Bake for 8 to 10 minutes or until cookies are set around the edges but still soft in the center. Don't over bake. The cookies will set up after they cool.

Step 9

Remove the baking sheet from the oven and let the cookies cool on the sheet for 3 to 4 minutes. Transfer to a wire cooling rack and cool completely. Continue baking the rest of the cookies.