Bone the chicken and cut the meat into thin slices or strips.
Place the chicken on a plate and pour over the Chinese wine.
Sprinkle over the cornstarch and stir together well. Leave to marinate for 30 minutes.
Blanch the bean sprouts in boiling, lightly salted water for 1 minute. Rinse under cold running water and set aside to drain.
Remove the chicken from the marinade with a spoon. Heat the oil in a wok and stir-fry the onions and the chicken.
Add the drained bean sprouts and the sugar. Stir in the marinade and the stock. Allow the chicken to cook through, which will take approximately 20 minutes. Check the seasoning, adding salt and pepper to taste. Serve immediately.
Use an ordinary onion if green onions are not available.
As soon as you add the marinade to the wok, the mixture will thicken so have the stock ready to pour in immediately and stir continuously until all the ingredients have been fully incorporated.