Pick over sprouts, discarding any needs. Heat half oil and quickly fry onion in it. Add 1 teaspoon chicken stock, tiny pinch pepper, good pinch salt and pinch Ve-Tsin and sprouts and sprouts and cook for 3 minutes, dish; keep hot. Wipe out pan. Add remaining oil; toss and cook the chicken pieces in it at a good heat for1 minute. Add 1/4 pint( U.S. 5/8 cup) chicken stock, sherry, seasonings and soy sauce. Stir in cornflour, blended with the water, and cook for a further 11/2 minutes. Put on bean sprouts. Serve.