Adjust oven rack to middle position and preheat oven to 375 degrees.
Whisk together flour, cream of tartar, cinnamon, baking soda and salt in a medium bowl and set aside.
Beat butter and white and brown sugars until creamy; add eggs and beat until combined. Stir in the flour mixture until just combined.
Roll dough into 1 inch balls and roll each ball in Spiced Vanilla Sugar. Place balls 2 inches apart on an ungreased baking sheet.
Bake 8-9 minutes. Transfer to a wire rack to cool.