Croquembouche is a derivation from "croque en bouche", French for 'crunch in the mouth'. It's a tower of cream puffs, sealed together with caramelized sugar. Traditionally, it's served as a wedding cake. They use a little hammer to break the thing apart for service.

Seems like a lot of work?

Yeah. It is. We all made one, working in teams. We didn't fill ours with anything first, so I suppose you could say we were cheating a little. But it was still a lot of work.