Prepare brownies as directed on package. Pour 2/3 the batter into greased pan. Place 12 – 15 Oreos on top and pour the remaining batter over it. Bake.
Once brownies are cool, melt chocolate chips and cream cheese in a small pot until combined well.
Add powdered sugar and vanilla and stir together.
Pour frosting over brownies and top with remaining Oreos that are crushed.