Was the composition of Elvish lembas ever discussed?

Question

Most accounts, such as exemplified in this answer here, present lembas as being a rarely-made / distributed and otherwise protected food.

Wikis never seem to give discussion on the matter, which leads me to think that no conceptual composition has ever been given - rather that its traits, effects, and consideration were Tolkien's intended impression.

---

LOTR:FOTR gives a comparison of lembas / waybread to other 'cakes' and such, but surely this only implies that lembas were produced from ground constituents that were held together with a binder (i.e. like any bread / cookie / biscuit / cake).

Is more said of lembas than this?

Answer 1

Yes, it was.

History of Middle-earth 12, The Peoples of Middle Earth, contains an essay titled "Of Lembas", which is a short discussion on the topic.

The primary ingredient is corn:

it was made of a kind of corn which Yavanna brought forth in the fields of Aman

But not just any old corn:

Now this corn had in it the strong life of Aman, which it could impart to those who had the need and right to use the bread. If it was sown at any season, save in frost, it soon sprouted and grew swiftly, though it did not thrive in the shadow of plants of Middle-earth and would not endure winds that came out of the North while Morgoth dwelt there. Else it needed only a little sunlight to ripen; for it took swiftly and multiplied all the vigour of any light that fell on it.

The actual making of the bread itself from this corn is, however, not known:

From the ear to the wafer none were permitted to handle this grain, save those elven-women who were called Yavannildi (or by the Sindar the Ivonwin), the maidens of Yavanna; and the art of the making of the lembas, which they learned of the Valar, was a secret among them, and so ever has remained.'

It's difficult to cite any more of this essay without just reproducing it in full - it really is that short. However, the last paragraph is sufficient to establish that the actual making of Lembas is not something we're ever going to know, and gives the reason why.

Answer 2

To add a bit to the other answer, we now a few additional details, thanks to some late c.1968 texts published in The Nature of Middle-earth. Note that these were composed some 10-15 years after "Of Lembas" in HoMe#12, and that Tolkien had apparently now decided that it was Oromë, not Yavanna, who taught this skill to the elves.

First of all we learn that specific variety of magic corn that Lembas are made from is called "Western Corn".

This “Western Corn”, it is said, slowly diminished in virtue on the Great Journey, owing to the dim sunlight, and there was no more Western Corn seed left when they arrived in Beleriand. But when the Noldor came back they brought with them new corn – and [it] by a special grace of pity by Manwë and Varda did not fail and was still in vigour till the end of the First Age. ... But at the time of L.R. only in Lórien did the Western Corn survive, ... With Galadriel’s departure and the death of Arwen, the Western Corn and Waybread were lost forever in Middle-earth.
_{The Nature of Middle-earth - "The Making of Lembas"}

We also have a very rough description of the steps involved in the making of the lembas.

[Oromë] brought as a gift from Manwë and Varda the seed of wheat, and instructed the Quendi in the manner of growing, harvesting, and storing it; but the grinding of flour, its kneading, and baking into (unleavened) “bread” was committed to the “bread-women”.*
_{The Nature of Middle-earth - "The Making of Lembas"}

It was made from meal [?ground] wheat-corn (specially brought to them by Oromë).
_{The Nature of Middle-earth - "The Making of Lembas"}

So it would seem the steps to get from Western Corn to Lemba involve "grinding", "kneading", and then "baking". Not a lot of detail, but this is all we're likely to get.