1.Prepare cake mix according to package directions for 2 9-inch round cakes. For easy removal from the pan, grease the bottom of the pan, then line it with a piece of parchment that has been cut to fit the bottom of the pan. Place the parchment in the pan and then grease the parchment and sides of the pan. Cook Cake according to the package. Allow to cool for 10 minutes and remove from the pan. then allow cake to cool completely.
2.Once cakes are completely cooled, prepare the filling by beating the cream cheese and sugar together with a hand mixer until well blended. Fold in the cool whip until almost blended then fold in the crushed oreos.
3.In another bowl, make the frosting by whisking together the cocoa powder and powdered sugar. Then add the butter, vanilla, and milk. Blend with a mixture until smooth. Add additional milk if needed to make the frosting spreadable.
4.Now it’s time to assemble the cake. With a serrated knife, cut off the domed top of each of the rounds to make the cake even and level. Save the parts you cut off for another use. Place one round on your serving platter or cake plate. Top with half of the filling mixture and spread evenly. Top with the other cake round.
5.Now use the reaming filling to fill in the center filling section of the cake so that the filling layer is completely even with the cake layers. You may not need all of the filling. Then cover the top and sides of the cake with the chocolate frosting. You may have some leftover frosting.