Duxelles is a mixture of finely chopped mushrooms, shallots and herbs cooked in butter. It is used to flavor soups and sauces, as a garnish, and a stuffing. Take a thinly pounded pork chop, veal or chicken cutlet, or even a flank steak. Spoon the precooked duxelles down the center. Roll the meat and then sauté or roast it.