Cut the pork into thin slices 5cm/1½in long. Put the slices in a bowl and mix them well with the shaoxing rice wine or dry sherry, soy sauce, sesame oil and cornflour. Leave to marinate for about 20 minutes.
Heat a wok or large frying pan until it is very hot. Add half the oil and when it is very hot and slightly smoking, lift the pork out of the marinade with a slotted spoon, put it in the wok and quickly stir fry it for about 2-3 minutes. Transfer it to a bowl at once.
Wipe the wok or pan clean, reheat it and add the rest of the oil. Quickly add the black beans, garlic, spring onions and shallots. A few seconds later add the rest of the ingredients. Bring the mixture to a boil and then return the pork to the work or pan. Stir fry the entire mixture for another 5 minutes. Turn it on to a warm serving platter and serve at once.
