Quite a while ago, I made some ganache for a cake (I used a 50/50
recipe) and froze the leftovers. I made way too much.

I was wondering if it can be thawed, melted & then whipped for a cake
filling?

Do I need to add anything to it?

Tips on how to do it? I read somewhere that you melt it in a double
boiler & add softened butter, but how much? I probably have about 3-4
cups of ganache. I's new to this, so any tips are greatly appreciated.

Also, how long do you think ganache will last frozen? I stored it in a
deep round Tupperware (real Tupperware) container & I think I put saran
wrap over the top of the ganache inside the sealed container. It's been
in there quite a while, but I know it hasn't been a year yet.

Thanks!