Remove cake domes from the tops of the cake with a large serrated knife. See my tips on how to level a cake and how to stack a cake.
Place the first layer of cake on a cake plate or cardboard cake circle. Pipe a dam of vanilla frosting around the outer edge of the cake. This dam will help keep all of the filling in place so that nothing seeps out or doesn’t stay in place.
Add about 6 tablespoons of chocolate ganache to the top of the cake and spread it into an even layer.
Add one cup of marshmallow frosting to the top of the ganache and spread into an even layer.
Add 1/2 a cup of graham cracker crunchies to the top of the frosting and spread evenly.
Add the second layer of cake, another dam of vanilla frosting, then another layer of ganache, marshmallow frosting and graham cracker crunchies.
Top the cake with the final layer of chocolate cake. Refrigerate the cake for about 30 minutes or so to make sure everything is stable.
Use the remainder of the marshmallow frosting to frost the outside of the cake. Feel free to use my tutorial for frosting a smooth cake.
Press the remaining graham cracker crunchies into the bottom part of the cake.
Use the remainder of the chocolate ganache to add the chocolate drip to the cake. See my tutorial for how to make a chocolate drip cake. It will have cooled off by now, so you’ll want to carefully heat it back up in the microwave.
Add some mini marshmallows to the top of the cake and use a kitchen torch to toast them.
Refrigerate cake until ready to serve. Cake is best when stored in an air tight container. Serve cool, but not cold and finish leftovers within 3-4 days.