Line bottoms of 3 - 8-inch pans with paper; grease and flour sides.
Crush Oreo's and set aside.
Mix flour, baking soda and salt set aside. Beat butter and sugar in large bowl with electric mixer on medium speed until light and fluffy. Add egg yolks, 1 at a time, beating well after each addition. Stir in vanilla. Add flour mixture alternating with buttermilk, beating until well blended after each addition.
Beat egg whites in another large bowl with electric mixer on high speed until peaks form. Gently stir into batter.
Add crushed Oreo's to batter and mix well.
Pour evenly into prepared pans making sure to have an even amount of batter in each pan.
Bake for 30 minutes or until toothpick inserted into centers come out clean. Immediately run spatula between cakes and sides of pans.
Cool 15 minutes; remove cakes from pans. Remove paper. Cool completely on wire racks.