Strawberry Yogurt Cake
["1 pkg. Betty Crocker super moist white cake mix", "3/4 c. water", "1/3 c. vegetable oil", "3 egg whites", "2 (6 oz.) containers Yoplait original strawberry yogurt", "1 (4 oz.) container frozen whipped topping, thawed", "red food coloring (optional)"]
["Heat oven to 350\u00b0.", "Grease and flour rectangular pan, 13 x 9 x 2-inch.", "Beat cake mix (dry), water, oil, egg whites and 1 container yogurt in large bowl on low speed 30 seconds .", "Beat on medium speed 2 minutes.", "Pour into pan.", "Bake 35 to 40 minutes or until cake springs back when touched lightly in center; cool completely.", "Fold remaining container yogurt and 1 or 2 drops red food coloring into whipped topping.", "Spread over top of cake. Garnish with strawberries if desired.", "Refrigerate any remaining cake."]
["white cake", "water", "vegetable oil", "egg whites", "containers Yoplait original", "frozen whipped topping", "red food coloring"]