This is prepared by frying together equal parts of mushrooms and parsley, a third of shallot or chives, and a little truffle (all minced separately), in fresh butter, seasoning it with salt, pepper, and a very tiny grate of nutmeg; stir this all over the fire for five minutes, then stir to it a large wineglassful of light French wine (or use the same quantity of sherry and water), previously reduced to half by sharp boiling; mix with the yolk of an egg and a dash of lemon juice. This mixture is often used as a garnish, and also as an addition to sauces, e.g., add a tablespoonful of the d'Uxelles to half a pint of veloute, bechamel, or allemande, for a white d'Uxelles, or the same amount of mixture to brown or espagnole sauce, for a brown one; either are then known as Sauce d'Uxelles, or aux fines herbes.