Levistus's_Leviathan
5e Freelancer
I've actually done something similar to that.You know one food the Elves might produce that’s no one can touch?
Maple syrup.
In my Eberron, in the forests of Aerenal where the Elves grow their magical trees (like the one that's lighter than air, the one that's hard as bronze, etc), there's another type of tree that has tree-sap that turns into Amber after a minute of being exposed to oxygen. The trees are coated in this thick, hard shell of solidified Ambersap (which is the name of the substance) that they gradually excrete. The stuff is so rare and is both expensive and extremely difficult to extract that the elves only export about 1,000 bottles of it each year in total, and each potion-bottle-sized bottle costs 1,000 gold pieces. (It's typically used as a high-grade adhesive, and the biggest buyers of it are the Dragonmarked Houses, but some renown artists also use the stuff in their work).