1 c. butter
1 c. sugar
1/2 c. sour cream
4 egg yolks
4 c. flour
1 tsp. vanilla
1 tsp. baking soda

Mix dry ingredients together. Cream butter and add sour cream and egg yolks. Add dry ingredients. Add flavoring. Chill dough for an hour or so and roll and bake at 350 degrees for 8 to 10 minutes.