Lorax, (good morning !)
They actually taste like banana custard. Because the tree has become more liked, they have even started making other cultivars of it, with slightly different fruit flavors. The original is still the best.
But for people like you and me, we cannot grow them. They have to have a chill factor of so many hours to set fruit, and i think (someone please correct me if I'm wrong here) you cannot grow them for fruit above zone...8? Some of the cultivars they've derived from original will take to zone 9, but none in 10 and up.
I ate them all the time when I was a kid up in Virginia. I've wanted to get some for years, but can't because of this! they're very tasty!
They remind me of huge green kidney beans for description. Nichole places link below for picture
Gino
Picture:
File:ARS pawpaw.jpg - Wikimedia Commons