2 1/2 c. sifted flour
1 tsp. baking soda
1/2 tsp. cream of tartar
1 c. (2 sticks) butter
1 1/4 c. sugar
3 egg yolks
1 tsp. vanilla

Preheat oven to 350 degrees. Grease cookie sheets. Sift together flour, soda and cream of tartar onto waxed paper. Set aside. Beat together butter and sugar in large bowl with electric mixer until fluffy, about 3 minutes. Beat in egg yolks and vanilla. Gradually add flour mixture in 4 parts, beating well after each addition, until well blended. Shape dough into balls, using a level tablespoon per ball. Place balls 2" apart on cookie sheets, do not flatten. Bake in preheated 350 degree oven for 12 minutes or until lightly golden around edges. Remove cookies to wire racks to cool. Makes about 3 1/2 dozen.