This is how it’s done: when you buy the ox, cut it into individual joints. Wash the ox tail and the marrow bones, cover them with water (1) and let them bubble for 3 minutes. Pour the meat pieces and the bones into a sieve, pour away the water, rinse the oxtail pieces and the bones thoroughly. Wash the cooking pot well so that no bone particles remain in it. Remove only the loose outer skin from one onion, then rinse the onion and cut it in half, unpeeled. Remove the peel from the other onion and cut it into eighths. Remove the peel from the carrots, celery and parsley, rinse and chop into small cubes. Heat the oil in a large saucepan and brown the oxtail pieces on all sides. Add the onions and the chopped vegetables and stir-fry. Add the bones, all the spices and the water (2) to the oxtail form and let it boil. Make the soup for half an hour, skimming again the foam that forms. Then remove the marrow bones from the soup, squeeze the marrow out of the bones, finely dice and put aside. Lightly make the clear soup following except for a split with the lid closed for 2 1/2 hours. Pour the soup through a hair strainer and cool the clear soup. Remove the meat from the oxtail pieces and cut into small cubes. Remove the fat from the cooled clear soup.