Gimli compares it to honey-cakes, I recall. It's described as a "very thin cake" but also as "crisp." Maybe a sort of unleavened bread?

I know a very basic cake recipe is flour, sugar, eggs and butter. I'm less sure what would go into unleavened bread--I'd have to research that.

Actually, honey might be an ingredient. It's a natural antibiotic and never spoils, which in part might play into how long it keeps and its restorative powers...