Someone created his own recipe for Lembas. I'm no good as a baker, but perhaps I can get my sister to make this. https://wastedlandsfantasy.blogspot.com/2010/12/lembas-elvish-waybread-real-world.html
I'm very familiar with AD&D (Advanced Dungeons & Dragons), but I'm not sure if that's what the author means by OD&D.
Something that might be easier to replicate without elven magic might be the twice-backed honey cakes of the Beornings.
OD&D has become the term for Original D&D, ie the original 1974 edition of the game.
Ah, so just D&D (D&D 1E). Weird; I don't think I've ever seen that before.
Me, I'm not a baker, so I'll just hand out the E.L. Fudge to my friends if they want Lembas.