The mother of all sauces, a derivation of espagnole [Spanish] sauce, a thick tomato sauce, demi-glace has become the sauce used as the basis for such savory sauces as Bordelaise, Madeira, Hunter's, Châteaubriand, Marsala and Romano, to name just a few.

Demi-glace is easy to do and can transform a dull, ordinary dish into a spectacular culinary achievement.

Theorically, it is 1/2 beef or veal stock and 1/2 espagnole sauce, reduced by about 90% to get a gelatin called 'glace'; reduced by 50% to get 'demi-glace' [half of full reduction].

Roast beef or veal bones in a preheated 450°F [230°C] oven.

Once bones are browned, add roughly iced onions, carrots and celery, tomato paste, red wine and flour, to thicken.

Season with bay leaves, whole black peppercorns, crushed chili pepper, rosemary and parsley stems - let roast for 30 minutes more.

Transfer contents of roasting pan to a large thick-bottomed sauce pot - add cold water to cover bones.

Let simmer, over medium heat, until reduced by 1/2, skimming occasionally the surface to remove unwanted fat, then stirring the bottom with a large wooden spoon to prevent sticking or burning.

The reduction should take approximately 5 hours, after which the demi-glace is carefully strained through 2 fine sieves.

Adjust consistency, using a mixture of cornstarch and water.

It is possible:

a - To vary the ingredients, skip the browning process and place bones and turkey carcass in a kettle filled with cold water.

b - Use whole vegetables - add whole tomatoes, tomato paste, parsley stems, whole black peppercorns, rosemary, thyme, red wine, garlic, mushrooms...

c - Thicken with lump-free thickener [flour briefly cooked in butter and diluted in hot water].

d - It should always be brownish, smooth and consistent.

e - It is ready when it coats a spoon evenly or very slowly runs off a plate when tilted.

f - Taste it one last time - add salt and pepper if needed.

g - Store demi-glace in portions suited for individual meals; use several samll containers instead of a large one or use ice cube trys, even plastic bags.

h - Refrigerate for up to 1 week or freeze it.

i - Laddle demi-glace over veal scallopines.

j - Laddle demi-glace over prime rib which has already been roasting on a bed of onions, carrots, celery and garlic, drained of excess fat; demi-glace not only bastes but also blends in with the prime rib juices.

Once ready, remove the roast and strain the sauce for a delicious prime rib sauce; there is no need to make it separately.

Also see recipe: 'Demi-Glace Sauce' in the sauce section [sau0191.htm].