Poppy Seed Cake
["1/2 lb. butter", "3 tsp. vanilla", "1 1/2 c. sugar", "4 egg yolks", "1/2 pt. sour cream", "1 tsp. baking soda", "2 c. sifted flour", "1 3/4 oz. dry poppy seed", "4 well beaten egg whites"]
["Cream butter and vanilla.", "Add sugar, egg yolks, sour cream and baking soda.", "Fold in flour, poppy seed and egg whites.", "Bake at 350\u00b0 for one hour in angel food cake pan."]
["butter", "vanilla", "sugar", "egg yolks", "sour cream", "baking soda", "flour", "egg whites"]