Wife tells me she would use royal icing rather than fondant. I'm not sure what the difference is.
I've never made royal icing but I believe it's made with egg whites. It's more "faffy" to make than fondant icing, which is much softer than royal icing. Royal icing is traditionally used on wedding cakes, although less so these days. It's a hard icing, but at the same time can melt in your mouth. When I was little, we used to have Christmas cake with royal icing and marzipan, but I would probably find it too sweet now on a whole cake.