Can I decorate with royal or buttercream icing over top of a fondant covered cake?
You can decorate on top of a fondant-covered cake with either, but Royal Icing will probably be better. Buttercream, over time, will soften the fondant, which may become gummy. (If you’re using buttercream, I’d say decorate it as close to serving time as possible.) Since Royal has no fat in it, it will not soften the fondant. Depending on what types of decorations you are doing, you can either do them directly on the cake, or do them ahead of time (like flowers) and let them dry thoroughly (24-48 hours), then attach them to the fondant covered cake with a little more Royal Icing to serve as the glue. Happy Decorating!
