2 1/2 c. all-purpose flour
1 tsp. baking soda
1/2 tsp. cream of tartar
1 c. (2 sticks) butter, softened
1 1/4 c. sugar
3 egg yolks
1 tsp. vanilla

Preheat oven to 350 degrees. Sift flour together with baking soda and cream of tartar onto wax paper; set aside.

Beat together, in a large bowl, butter and sugar until fluffy, about 3 minutes. Beat in egg yolks and vanilla. Gradually add flour mixture and beat well until all is blended. Shape dough into balls, about 1 tablespoon for each ball. Roll balls in sugar and place 2" apart on cookie sheets. Do not flatten. Bake in 350 degree oven for 12 minutes until lightly golden brown around edges. Remove to cooling rack to cool. Yield: about 3 1/2 dozen.