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