Now if you are ambitious you can make your own batch of cookie dough or you can just buy it already made up. One tube of it will do the trick. Spray nonstick cooking spray in the bottom and up the sides of a 9 x 13 baking dish. Place the cookie dough in the bottom of the dish, pressing it out so that it is evenly distributed. Put the Oreo cookies on top of the cookie dough. I did 3 rows of 6 cookies. Mix up your brownie batter according to the box directions and pour over the Oreo layers. Use a spatula and smooth it around so that it is evenly distributed. Put in a 350 degree oven and bake for 45-55 minutes. Makes 24 tasty treats!