Finally, I got around to making this Oreo cake! I had made the cake layers in advance and frozen them. The layers are made with my Hershey’s cake recipe. The filling is made with an Oreo frosting. I had tried to use marshmallow fluff but apparently this should have been folded into the frosting because when I beat it in my mixer, it turned into a sticky gooey substance. I had to toss it out and star over.