1 c. unsalted butter
1/2 c. sugar
1/2 c. brown sugar
1 egg
1 tsp. vanilla
2 1/2 c. all-purpose flour
1 tsp. cream of tartar
1 tsp. baking soda
1/2 tsp. salt

Cream butter and sugar, add egg and vanilla. Stir in flour mixed with cream of tartar and baking soda. Form small balls. (Refrigerate dough on hot days before forming balls.) Put on ungreased cookie sheet, flatten with glass that has been dipped in fine sugar. Bake at 350 degrees for 10-15 minutes, or until lightly browned.