Cut the sole into long thin strips. Beat the egg whites, cornflour and salt until frothy, then pour over the fish, mixing well. Chill for 20 minutes.

Heat the oil in a wok or large frying pan. When nearly smoking, add the fish and stir-fry over a fairly high heat for 2 minutes. Remove from the pan with a slotted spoon, then discard all but 1 tablespoon of the oil. Add the ginger and garlic and stir-fry for 1 minute, then pour in the soy sauce, sherry and fish stock.

Bring to the boil quickly, then bubble for 2 minutes. Return the fish to the pan and heat through for 1 minute, stirring constantly. Pile on to a warmed serving dish, sprinkling with trie spring onion strips and serve at once.