This classic sauce for beef or lamb can be modified into a multitude of other classic sauces by changing an ingredient or two. Change the Madeira to Marsala, sherry, sauterne, vin de paille, or other sweet wine. Before adding the wine add some cognac, marc, grappa, or other alcohol to deglaze the shallots and reduce it totally. Substitute beef, pork, or some other meat demi-glace for the veal. Use some minced truffles instead of the lemon confit. All these changes are possible and a nice sauce will still be the result.