Duxelles

Duxelles is cuisine French (not in standard French dictionaries) designating a mixture of chopped mushrooms sautéed in butter with onions and/or shallots and used as a garnish with many dishes.

Why this mixture is called a duxelles (or Duxelles) is the subject of much conjecture. One school argues that it was named after the Marquis d’Uxelles whose cook, la varenne, wrote a popular cookery book in the 17th century (La Varenne himself, however, does not include a recipe for duxelles nor does he use this term).