Cut the beef into 5cm/2 inch cubes, using a Chinese cleaver or a sharp knife. Trim away any excess fat.
Place the beef in a flameproof casserole or heavy pan with the ginger, salt and water. Bring to the boil and boil for minutes; skim.
Lower the heat, cover and simmer very gently for 2 ½ to 3 hours. Meanwhile, make the dips. Mix 2 x 15 ml spoons / 2 tbsps soy sauce with the ginger in one bowl. Put the hoisin sauce in a second dish, the mustard in a third, and mix the chilli oil, chilli sauce and remaining soy sauce in a fourth dish.
Add the spinach to the casserole and simmer gently for a further 1 to 2 minutes. Sprinkle with the coriander (Chinese parsley). Serve in individual soup bowls accompanied by rice. To eat this semi-soup, each diner lifts the meat out of the broth with chopsticks and flavors it with the dips. The broth is spooned into the rice bowls and eaten with the rice.