The Collaborative International Dictionary of English v.0.48:
marchand de vin \marchand de vin\ n. (Cookery) A sauce consisting of brown sauce with mushrooms and red wine or madeira. Syn: mushroom wine sauce. [WordNet 1.5]WordNet (r) 3.0 (2006):
marchand de vin n 1: brown sauce with mushrooms and red wine or Madeira [syn: marchand de vin, mushroom wine sauce]