“Cook they hadde with hem for the nones,
To boil the chiknes with the marybones,
And poudre-marchant, tart and galingale.
Wel coude he knowe a draughte of London ale. (Chaucer, 1386) General Prologue 381.
Some people read the line in question above without the comma: ” And poudre-marchant tart and galyngale”, thus speculating that it was a tart-flavoured powder. There is also a theory is that Chaucer meant “poudre” to be used as a verb (even though the word poudre-marchant is hyphenated.)
“I think it will become obvious, on considering them attentively, that poudre, after all, is not a noun, but a verb. The coke (sic) was to “boile the chickenes [sic] and the marie bones [sic],” and [to] poudre the the things which follow, viz. marchant, tart, and galingale…. ‘To poudre’ meant in old English ‘to salt.’ But poudre stood also for various condiments, e.g. for a certain mixture of warm spices, pepper, ginger, etc…..I would therefore take the verb ‘to poudre’, in the above lines of Chaucer, as signifying ‘to season’; that is, by sprinkling some such condiments on the articles to be served up. The corresponding term of modern cookery is ‘to dust.’ In a separate paper I hope to give a good account of ‘marchant.'” — Boys, Thomas. in Notes and Queries. London: Bell & Daldy. Series II, Volume 5. 9 January 1858. Page 25. [Ed: We have been unable to locate any of the promised followup to account for the word “marchant” by itself there.]