Ok, I have been using the same BC recipe for years (1/2 butter, 1/2 shortening), but lately I have been getting air bubbles that form between the cake and the frosting. I always cool my cakes overnight, so they are not warm when I ice them. I just can't figure it out! The only thing I can think of is that it has been humid here lately, but I decorate in the AC soooo.....can anyone give me some clues as to what is going on?? It's driving me crazy cause it messes up my purty icing when I have to pop and fix bubbles! Thanks in advance!