Cream together the butter and sugars. Add the egg and vanilla and beat until smooth.
Add flour, salt, baking soda, and cream of tartar. Mix.
Refrigerate dough for 30-60 minutes.
Scoop a small amount of dough and roll into a small ball. Roll in cinnamon/sugar topping mixture.
Bake cookies at 350 degrees for 12-14 minutes. They'll seem underdone, but they'll finish after removed from the oven.