Preheat the oven to 350 F. In a medium bowl, whisk together flour, salt, baking soda, cream of tartar and cinnamon.
In a large bowl, combine butter with stevia until fluffy. Add in egg and vanilla extract, and mix until smooth. Add in the flour mixture, mix until it is fully combined.
In a shallow dish, combine granulated stevia and cinnamon. Roll the cookie dough into balls, and roll them into the cinnamon mixture. Place cookies onto a large ungreased baking sheet at least 2-inches apart. Bake for 10-12 minutes.
