Can anyone tell me what would cause the frosting to bubble from the side of a cake. The last two cakes that I've done, I have left out overnight in a box and when I open them up in the am to finish decorating the frosting has an air bubble under it. Like the size of my palm. I poke a hole in it and press it back down but you can still see where the frosting had moved. These cakes had fondant decoration on them so i didn't store them in the fridge because i didn't want the moisture to get to the fondant when they warmed up. I seems like if i refrigerate a cake I have problems with the moisture in the fondant. If i don't refrigerate i have problems with the frosting. Any suggestions?

Try lfilling and crumbcoating your cakes and then etting them 'settle' overnight before putting your fondant on - this should help.

Were your cakes at room temp when you iced them? If not, as the cold inside the cake exits, it has nowhere to go if the cake is "sealed" with buttercream (or fondant) and an air pocket forms.

Maybe this will help....

I don't know what the answer is either. From time to time, even though I crumb coat my cake, give it time to settle overnight, then frost the cake, let that settle for many hours or overnight, then put on the fondant decorations, I can still get an air bubble. Just happened to me, so I poked a hole in it (mine was buttercream frosting), pressed it back down and put another fondant decoration over it! But in some cake designs, that wouldn't be possible.