Preheat the oven to 400 degrees. Spread the bones out in one layer in one very large or two smaller sturdy roasting pans. Roast in the oven for 1½ hours, stirring every 30 minutes. The bones should have a nice brown color but not be burned. Peel the onions if the skins are dirty or spoiled, and quarter. Add the onions and carrots to the bones, and continue cooking, stirring a few times, for an additional 30 minutes.

Using a large skimmer or tongs, lift the bones and vegetables from the roasting pan(s), and place them in a large kettle or stockpot (20-quart capacity), preferably stainless steel. Pour out and discard the fat that has accumulated in the roasting pan(s), and add enough water to the pan(s) to cover the bottom. Set over medium to high heat, and scrape the bottom of the pan(s) with a flat-ended wooden spatula to release and dissolve the solidified juices. Add the contents of the pan(s) to the stockpot.

Fill the pot with water to within 2 to 3 inches of the top, and bring to a boil, which may take as long as 45 minutes. Boil gently for 2 hours, then skim off as much fat as you can from the top. Add the garlic, parsley, celery, bay leaves, thyme, peppercorns, and tomatoes, and bring back to a boil. Boil very gently for about 4 hours, for a total of 6 hours. Strain the stock through a very fine sieve, and set it aside to cool. The yield should be about 5 quarts.

When the stock is completely cold, remove and discard any fat that has come to the top. The stock should be transparent, practically fat-free, salt-free, and slightly gelatinous.

To make demi-glace, a reduced brown stock:

Boil the stock down over high heat until reduced to 2½ quarts. It should be highly gelatinous, slightly syrupy, and have a beautiful reddish-brown color. Freeze in small containers.

For the glaze and meat extract:

To the bones, which have already been cooked, add enough cold water to fill up the kettle again. Bring to a boil, and again boil the bones gently for 5 to 6 hours. The stock yielded won’t be as clear as the first stock, because the bones will be breaking down into a paste. The resulting stock will be slightly cloudy but quite tasty. Strain, and reduce the stock over high heat in a large kettle. As the liquid reduces, transfer it to a smaller pan, and continue to reduce. You will notice that when it is completely reduced the mixture is as dark as caramel. Large bubbles will appear on the top, and the texture will be very thick, like jam. Be careful to cook over very low heat during the last hour of cooking, so the glaze doesn’t scorch. Pour into a bowl, and cool. The yield should be about 1½ cups. When cold, cut into 1-inch cubes, wrap well, and freeze for future use.

Fast brown stock:

Brown stock can also be made in smaller quantities on top of the stove: Cut about 2 pounds of chicken bones into 1-inch pieces, and brown them, turning occasionally, in a sturdy pot over medium heat for about 45 minutes. Pour out the rendered fat. Add enough water to cover the bones by 2 inches, and 1½ cups diced mixture of onions, carrots, and celery. Cook for about 5 hours, adding more water as needed. Strain, and cool.

Yield: 1 quart