Was your cake still slightly warm when you filled it. The biggest reason a filling bulges out is because there's too much of it. They say to make a dam 1/4" in from the outside rim then fill the center of the dam. When you put the top on, it has 1/4th of an inch to settle in to. And I would add extra chocolate to your ganache. Sounds like it needs it to set up properly and hard.
10/4/14 at 9:49am