Red Velvet Swirl Cake
["1 pkg. white cake mix", "3 egg whites", "1 5/6 c. buttermilk - divided", "2 Tbsp. vegetable oil", "1/2 pkg. yellow cake mix", "1 large egg", "1-1/2 Tbsp. cocoa", "1/2 tsp. baking soda", "2 Tbsp. red food coloring", "1 tsp. cider vinegar"]
["Beat White cake mix, egg whites, 1-1/3 c. buttermilk and vegetable oil until creamy. In a separate bowl, beat yellow cake mix,", "1/2 c. buttermilk, whole egg, cocoa, soda, food coloring and vinegar until creamy.", "Alternate spooning red and white batter into 3 greased and floured 9-inch cake pans.", "Swirl batter gently with a knife - (do not scrape bottom of pan).", "Bake 350\u00b0 for 25 minutes."]
["white cake mix", "egg whites", "buttermilk", "vegetable oil", "yellow cake", "egg", "cocoa", "baking soda", "red food coloring", "cider vinegar"]