In a mixing bowl beat Butter with an electric mixer on medium for 30 seconds. Add 2 C. Flour, Sugar, Egg, Vanilla, Salt, Baking Soda, 1 tsp. Cinnamon & Cream of Tartar. Beat until thoroughly combined. Beat in remaining Flour.
Cover with plastic wrap and chill in the refrigerator for at least an hour. If you are short on fridge space, wrap the dough up in plastic wrap tightly and put in the fridge that way.
In a small bowl combine 1/2 C. Sugar & 2 T. Cinnamon. (Sometimes I find that it takes more than this so I just add additional Sugar & Cinnamon to my bowl as needed.)
Preheat Oven to 375.
Shape dough into 1-inch balls, roll in Cinnamon Sugar mixture and place on an ungreased cookie sheet. Bake for 10-11 minutes or until edges are golden.
Makes 4-5 dozen, depending on size.