1/2 c. powdered sugar
1 tsp. baking soda
1 tsp. cream of tartar
1/4 tsp. salt
1 c. butter
1 egg
1 tsp. vanilla
2 1/2 c. flour

Mix ingredients on low speed about 1 minute. Blend well. Chill dough 15-30 minutes before shaping. Shape 3/4 inch balls. Place on cookie sheet, about 2 inches apart. Flatten balls with fork. Sprinkle with sugar. Bake at 350 degrees for 5-8 minutes until set but not brown. Let cool on cookie sheet about 1 minute. Store loosely. 4 dozen.