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 with sugar until fluffy.
Add in egg and vanilla extract, and mix until smooth. Add in the flour mixture, and mix until it is fully combined. Fold in sprinkles. In a shallow dish, combine granulated sugar and cinnamon.
Roll the cookie dough into balls and roll them into the cinnamon sugar mixture. Place the cookies onto a large ungreased baking sheet. Bake for 10-12 minutes.
