Do you use real butter, or shortening? My buttercream is very simple. Just butter, powdered sugar, and heavy whipping cream. I get the best reviews about it. But, have had a couple of times where it gave me trouble. Not very often though (really only like 3 or 4 times in the last 4 years). But, I think that's partly because of how I normally work with it. The couple of times I had issues with the buttercream itself, it was well over 115 degrees outside.