Combine the rice wine, soy sauce and oyster sauce, and set aside.
Heat the oil in a wok until very hot and stir-fry the garlic for a few seconds. Add the prawns and stir-fry briskly until they change colour. Add the peas and oyster sauce mixture, and stir-fry for another 30 seconds, then add the water and bring to a boil. Thicken the broth with the cornstarch and