I am making a wedding cake this weekend out of fondant and there is piping on it. I was going to use royal icing because I thought that would hold up the best but I am concerned that since I use shortening when working with my fondant, the grease could affect or break down the royal icing. Has anyone had a problem with this before?
Never...fondant can hold anything well especially royal icing. But remember it dries rock hard so if you are doing a lot of piping you might want to think about how that may taste for your customers. Buttercream works equally well, just add some meringue powder to your buttercream so it crusts over well. Hope this helps and good luck
You can pipe royal icing directly on fondant or on buttercream, for that matter. Royal icing breaks down when grease is introduced to the icing WHILE IT IS MIXING. Once the icing is made, you can pipe flowers on foil that has been greased with vegetable oil, shortening, spray Pam or whatever ~ and the royal icing will dry beautifully without problems.