Preheat your oven according to the brownie mix instructions.

Prepare the brownie batter as directed on the box and bake in a greased 9x13 inch pan until cooked through. Let them cool completely.

In a large mixing bowl, beat the softened cream cheese until smooth. Gradually add the powdered sugar and vanilla extract, mixing until well combined. Gently fold in the whipped topping.

In another bowl, crush the Oreo cookies into small pieces using a food processor or by placing them in a zip-lock bag and crushing them with a rolling pin.

Once the brownies are cool, cut them into squares.

In a trifle dish or a large bowl, layer the ingredients starting with a layer of brownies, followed by a layer of cheesecake mixture, and then a layer of crushed Oreos. Repeat the layers until all ingredients are used, finishing with Oreo crumbles on the top.

Cover the trifle with plastic wrap and refrigerate for at least 2 hours before serving.

Drizzle chocolate sauce on top before serving if desired.