1 1/4 c. sugar
1 c. unsalted butter, softened (or 1/2 butter & 1/2 butter)
3 lg. egg yolks, slightly beaten
1 tsp. vanilla
2 1/2 c. sifted flour
1 tsp. baking soda
1/2 tsp. cream of tartar

Preheat oven to 350 degrees. Lightly grease the cookie sheets. Cream together the butter and sugar until it is light. Beat in egg yolks and vanilla. Sift together flour, soda and cream of tartar. Fold the dry mixture into the butter-sugar mixture.

Form dough into walnut sized balls. Place 2 inches apart on cookie sheet. Do not flatten. Bake about 11 minutes until cracked and just turning color. Cool on rack. Makes 4 dozen.