1/2 lb. butter
3 c. sugar
1/4 tsp. baking soda
6 eggs
1 tsp. vanilla
1/2 pt. sour cream
3 c. plain flour

Cream butter and sugar; add 6 egg yolks and beat until lemon color. Add sour cream and flour into which the soda has been sifted. Beat well and add vanilla. Beat the 6 egg whites until stiff and fold into batter. Place in cold oven, turn to 350 degrees for 15 minutes. Reduce heat to 300 degrees. Bake for 1 hour or until knife comes out clean.