1. Preheat the oven to 350 degrees F.
2. Line a 9x13" baking tray or two 8x8" baking dishes with parchment paper or spray with non stick cooking spray.
3. In a large bowl, combine the ingredients to make the cake batter. Mix with a hand mixer or electric mixer as directed on the box.
4. Add 1 cup of crushed Oreos to the batter, reserving 1/3 of the Oreos for topping.
5. Bake the cake as directed on the package of cake mix. This is typically 25 minutes for an 8x8" pan.
6. In a medium bowl cream together cheese, sugar and vanilla until smooth. An electric mixer works well for this but you could also using a stand mixer with the paddle attachment.
7. Fold the cool whip into the cream cheese mixture.
8. Spread the frosting overtop of the cooled cake.
9. Top with the reserved crushed Oreo cookies.