Step 1

Preheat the oven to 350°F. Spread the Oreo cookies evenly over the bottom of a greased 13x9-inch baking dish.

Step 2

Spread the sweetened condensed milk over the cookies. Next, evenly spread the whipped topping over the top, then sprinkle on the chocolate chips. Sprinkle on the cake mix, spreading it evenly into a flat layer, then top it all with the cubed butter.

Step 3

Bake the Oreo dump cake until the filling is bubbly and the top is golden brown, 40 to 45 minutes. Serve the cake warm with chocolate sauce and sweetened whipped cream, if desired.