Preheat the oven to 350°F and line a 9×13 baking dish with parchment paper or aluminum foil. Coat with cooking spray. Set aside. In a large mixing bowl, combine the brownie mix, vegetable oil, water and eggs. Set aside.
Fold one part of the Oreos into the brownie batter. Pour the batter into the prepared baking dish. Top the brownies with the remaining crumbled cookies. Bake for 23-26 minutes or until the center has set. Remove and allow to cool fully.