Mile High Buttermilk Cake
["4 c. sifted cake flour", "1 tsp. baking soda", "1/2 tsp. baking powder", "1/2 tsp. salt", "1 c. butter or margarine", "3 c. sugar", "1 Tbsp. vanilla", "2 c. buttermilk", "6 egg whites", "Creamy Vanilla Filling", "Orange Butter Frosting"]
["Sift together cake flour, baking soda, baking powder and salt. Cream together butter and sugar until light and fluffy.", "Beat in vanilla.", "Add dry ingredients alternately with buttermilk, beating well after each addition.", "Add egg whites; beat at medium speed 2 minutes.", "Pour batter into three waxed paper-lined 9-inch round cake pans.", "Bake at 350\u00b0 for 20 minutes.", "Reduce heat to 325\u00b0 and bake 25 more minutes or until cake tests done.", "Cook for 10 minutes.", "Spread Vanilla Filling between layers of cake.", "Top with Orange Butter Frosting."]
["cake flour", "baking soda", "baking powder", "salt", "butter", "sugar", "vanilla", "buttermilk", "egg whites", "Vanilla Filling", "Orange Butter"]