I am making a grad cake and I would like it all edible. I am using a ball cake pan for the cap part but trying to figure out how to make the square board. Any suggestions besides using card board?
I have tried melting chocolate into a square pan but then I cant get it back out, even using wax paper.

I used fondant mixed with tylose powder (or you could mix it with gumpaste). While technically it is edible, I wouldn't eat it as it dries hard and I wouldn't want to take the chance of someone cracking a tooth on it.

If you truly want an edible (and tasty) board, you could melt some black candy melts, spread it out evenly in a 5" square (or approrpiate size), let it cool, then carefully peel it off your waxed paper.

Pour out your molten material onto a sheet of kitchen parchment paper.

I make it from gumpaste . Let dry several day. If using chocolate, I would make modeling chocolate, roll out, cut 5x5, let dry several days. That could be eaten and not be as fragile as just using melted chocolate. Either would be fine, not knocking anyone elses replies. . hth