Preheat the oven to 230°C/450°F/regulo 8.
Put the bones into a roasting tin and roast for 30 minutes or until the bones are well browned. Add the onions, carrots and celery and return to the oven until the vegetables are also browned. Transfer the bones and vegetables to the stock pot with a metal spoon. Add the bouquet garni, peppercorns, cloves, garlic and tomato purée. De-grease the roasting pan and de-glaze with some water, bring to the boil and pour over the bones and vegetables. Add the rest of the water and bring slowly to the boil. Skim the stock and simmer gently for 5–6 hours. Strain the stock, allow it to get cold, and skim off all the fat before use.
This stock will keep for 2–3 days in the refrigerator. If you want to keep it for longer, boil it for 10 minutes, and then chill again. It can also be frozen.