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 color (if desired)

Heat oven to 350 degrees. Grease and flour rectangular pan, 13 x 9 x 2 inches. 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 1 container yogurt and 1 or 2 drops red food color into whipped topping. Spread over top of cake. Garnish with strawberries, if desired. Refrigerate any remaining cake.