Cut the meat into 5cm (2in) cubes. Next, blanch the lamb by plunging it into boiling water for 5 minutes. Then remove the meat and discard the water. Slice the spring onions at a slight diagonal into 7.5cm (3in) pieces.

Heat a wok or a large frying pan over a high heat until it is hot. Add the oil, and when it is very hot and slightly smoking, add the pieces of lamb and stir-fry them until they are brown. Add the spring onions, ginger and onion to the pan and continue to stir-fry for 5 minutes. Transfer this mixture to a large flameproof casserole or pan and add the braising sauce ingredients. Bring the liquid to the boil, skim off any fat from the surface, and turn the heat down as low as possible. Cover and braise for 1½ hours, or until the lamb is quite tender, skimming off any surface fat from the sauce.

Arrange the cooked meat on a platter and serve with the sauce. Any leftover sauce can be frozen.