Sour Cream Cake
["1/2 lb. butter", "2 c. sugar", "4 egg yolks", "2 tsp. vanilla", "3 c. cake flour", "1 tsp. baking powder", "1 tsp. baking soda", "1 pt. sour cream"]
["Mix all ingredients in order.", "Mix well until well blended. Beat 4 egg whites until stiff.", "Fold into batter.", "Add 1/2 cup chopped nuts, if desired.", "Place in well-greased and floured 9-inch tube pan and bake for approximately 1 hour at 350\u00b0."]
["butter", "sugar", "egg yolks", "vanilla", "cake flour", "baking powder", "baking soda", "sour cream"]