"Duxelles", cooked chopped mushrooms and shallots, is one of the best secrets of French cooking. A little bit enriches a sauce, more makes a soup, more still, a stuffing for fish. Use 2 tablespoons or so to fill an omelet. Substitute Duxelles for meat in Lasagne for a vegetarian dish of singular complexity of taste./ Freeze some Duxelles in ice cube trays, then store in plastic bags, for days when you want to toss just one or two cubes into a Bechamel or pasta sauce. Freeze in larger quantities for use as a stuffing./When cooking Duxelles, you may see a little butter in the mixture at the end of the cooking time, but there should be no mushroom liquid left. If there is, continue to cook, uncovered 1 or 2 more mins until it has evaporated. The cooking time varies, depending on the size of the chopped mushrooms; the larger the mushroom pieces the shorter the cooking time.