I'm testing some buttercream recipes for a wedding cake I'm making. I'm considering doing an 'American' buttercream, as honestly I don't have a stand mixer and last Christmas I tried to make royal icing and it just didn't fly. I can't peak those eggs, no way no how. Powdered meringue, equally sad. So, I'm doing unsalted butter-confectioners-milk (or maybe cream) and vanilla (have the colorless kind). THe one I made lastnight I made rather thick so it can stand up to being exposed for a time and all the sugar made it grainy. Any suggestions? and what do people think about adding a few spoons of shorteniing for stability? I added a bit to see what it would be like and didn't notice anything odd.