Preheat the oven to 400 degrees. Spread the bones on a roasting pan and roast for 30 minutes. Add the onions and carrots, and continue roasting for 30 minutes longer, stirring the meat and vegetables once or twice. Remove from the oven and place all of the roasted ingredients in stockpot or kettle. Deglaze the roasting pan with two cups of water and pour this liquid over the meat and vegetables. Add the remaining water and ingredients to the stockpot. Bring the mixture to a boil. Boil for 15 minutes, and then reduce the heat to medium-low and simmer for 4 hours. At the end of the 4 hours, pour the entire contents of the stockpot through a colander or sieve. Cool. Chill the stock overnight and then remove the fat that has accumulated on the surface. Stock is ready to use or freeze.
Makes about 2 quarts