Mushroom sauce
Appearance
Mushroom Sauce
Ingredients: Velute sauce, essence of mushrooms, butter.
Mix two dessert-spoonsful of essence of mushrooms with a cupful of Velute sauce, reduce, keep on stirring, and just before serving add an ounce of butter. This sauce can be made with essence of truffle, or game, or shallot.
Source: The Cook's Decameron: A Study In Taste, Containing Over Two Hundred Recipes For Italian Dishes from a project that puts out-of-copyright texts into the public domain. This is from a *very* old source, and reflects the cooking at the turn of the last century. Update as necessary.