Whether your magical recipe calls for an uncommon herb out of season or something as rare and illegal as mumia (the bitumen of the embalmed body of an ancient Egyptian), the unavailability of an ingredient need not stir up trouble. The simple answer is illuminated by the highly specialized field of Transcendental Hyperontology. In a nutshell, the very structure of the recipe itself holds the key, as the words constitute an efficacious mantra. Put another way, the recipe can be chanted so as to bubble in the cauldron of the mind.
The wisdom of speaking aloud the names of ingredients has bled into popular culture. Consider Shakespeare's Weird Sisters in Macbeth. As Harald W. Fawkner explains,
[T]he sisters 'celebrate' language, because when they chant the recipe for the demonic broth to be stirred in the cauldron, Shakespeare makes us feel that language itself, its formulaic procedure, is structurally equivalent to the demonic recipe. The weird quality in the broth is as it were not only a function of the recipe as material substance (what empirically gets thrown into the cauldron) but equally so a function of the recipe as language. You cannot simply make the broth without chanting its formula, and conversely you cannot chant the formula without making the broth: the two operations, that of language and that of weird doing ... can be taken literally when it comes from witchcraft, for it is clear that Shakespeare often gives us the impression that the Weird Sisters only have to think something to create it. I suspect indeed that Shakespeare would not have been hostile to the idea of letting the witches perform the 'making' of the brew in terms of mimicry, without any empirical kitchen-work at all. In this sense what I said above could be taken literally: you cannot chant the formula without (automatically) making the broth. (Deconstructing Macbeth: The Hyperontological View, 1990, pp. 70-71).
From the sublime to the ridiculous, consider the sitcom Bewitched, in which protagonist Samantha emptyhandedly invokes "hummingbird and dragonfly wings," while the family doctor conjures with a verbal "ear of corn / tooth of comb."
Like those of witchcraft, the traditional recipes of alchemy were in fact mental and spiritual endeavors. Psychologist Carl Jung disclosed that the material substances and procedures were only a projection of an alchemist's internal state, while the real substance being transformed was the mind itself.
Hence, back when I was a starving student, when I couldn't afford a particular bottle of Ayurvedic herbs, my meditation teacher whispered to me that I could simply chant the name of the medicine, "Amrit." As neuroscientist Candace Pert has proven, thoughts make molecules.
During setbacks due to a scarcity of magical ingredients, we can reverse Marshall McLuhan's famous phrase, "the medium is the message." The message (the recipe) is in fact the medium (the substance).
Your comments about words creating concrete realities in one of your latest posts would raise no eyebrows among Old Testament scholars. The Hebrews, in common with other ancient Near East and African cultures, believed that words seriously spoken in proper form were as tangible as a document, or a rock. When Jacob impersonates his brother Esau in order to receive the firstborn's blessing from his blind father Isaac, he really does get the thing. When the ruse is later discovered, it occurs to no one to argue that Jacob's blessing may now be considered invalid because Isaac's intention is the important thing. Esau may weep and beg, and Isaac may fume and regret, but the patriarch can now only muster a second-rate blessing to give to poor Esau. There is no legal recourse. The words were spoken.
Incidentally, did you know that "the ten commandments" is really "the ten words" in Hebrew? The common, ordinary word that means "words" is used. Translators continue to use "commandments" because the publishers will not accept the more accurate "words." After all, who will buy a Bible in which Moses is given The Ten Words?