In a large bowl, combine all cake ingredients, except crushed cookies, at low speed until moistened. Beat 2 minutes at highest speed. Gently stir in 1 cup coarsely crushed cookies. Pour batter into prepared pans. Bake for 25-35 minutes or until toothpick inserted in center comes out clean. Cool 10 minutes. Remove from pans and cool completely.
For frosting, in a small bowl, combine 1/2 cup of powdered sugar, shortening, vanilla, and egg whites. Blend well. Beat in remaining powdered sugar until frosting in smooth and creamy. Fill and frost cake. Garnish with OREO Cookies and/or cookie crumbs.