Sound similar to the "Oat & Syrup" concoction that was baked to a hard glaze that even the hot custard could not penetrate.Yes we had that, lovely. We also had a pud we called concrete, it was brown and incredibly hard. Nowadays they would make you wear a hard hat and safety goggles to tackle it. It was common to bend spoons trying to dig into it, when the spoon did manage to penetrate it, it would shatter and bits would fly everywhere.
Col
Was a good mouthful to chew though once you broke a bit off.