Combine the milks, cream, chocolate, vanilla extract, salt and nutmeg together in a large saucepan and stir constantly until the chocolate is melted and the mixture is heated through. Pour the hot chocolate into mugs and top with a tablespoon or two of the marshmallow cream. The marshmallow is super thick and rich, so keep that in mind when it comes to adding your desired amount. Torch the frosting on top if desired. I suggest serving this with a spoon since the marshmallow may get all over your face!