I crumbcoat my cakes and leave them in the refrigerator overnight to set. I remove the cake the next day and allow it to come to room temperature – then I cover it with fondant. If you cover a cake with fondant while still very cold, you will get air bubbles and bulges because as the cake comes to room temperature, it will expand. The sticky fondant may be a combination of the cold cake underneath coming to room temperature and the humidity level in your home.
Fondant will eventually dry – once covered, let it rest without touching it. You may want to put a fan in front of it to expedite the drying process.
You will always have to trim the bottom of the cake – it would be difficult to rolll out fondant to the exact size of the cake.
I don’t know if my method is the correct one, but it has worked fine for me.
Good luck and don’t get anxious – it willl be fine!
DJ - Fun Fiesta Cakes
