Assemble the cake: Cut each cake in half to create 4 layers. Place a layer of cake on a stand. Spread half of the nougat cream over the chocolate cake, layer. Place another cake layer on top and spread half of the caramel buttercream. Place a third layer of cake, and spread the remaining nougat cream. Place the final chocolate cake layer, flat side facing up, and cover the top and sides with the caramel buttercream. Reserve 3 tablespoons of the caramel frosting for later. Place the cake in the fridge for 30-40 minutes.