CAKE:

1 box white cake mix
1 1/4 c. water
1/3 c. oil
3 egg whites
1 c. crushed Oreos

FROSTING:

3 c. powdered sugar
3/4 c. shortening
1 tsp. vanilla
2 egg whites

Preheat oven to 350 degrees. Grease and flour 2 (8" or 9") round cake pans. Combine all ingredients except Oreos; mix at low speed until moistened; 2 minutes at highest speed. Stir in Oreos. Bake for 25 to 35 minutes. Cool 10 minutes and remove. Cool. Combine 1/2 cup powdered sugar and rest of ingredients; blend well. Beat in remaining sugar until smooth and creamy. Fill and frost cake. Garnish with Oreos.