• Heat the oil in a wok, swirling it around until really hot. Add the spring onions (scallions) and stir-fry for a minute then add the carrots and mushrooms and continue to cook for about 2 minutes.
• Add the stock and bring to the boil then season to taste with salt and pepper, five-spice powder and soy sauce and simmer for 5 minutes.
• If the prawns (shrimp) are really large, cut them in half before adding to the wok and simmer for 3-4 minutes.
• Add the watercress to the wok and mix well, then slowly pour in the beaten egg in a circular movement so that it cooks in threads in the soup. Adjust the seasoning and serve each portion topped with a whole prawn (shrimp).

COOK'S TIP

• The large open mushrooms with black gills give the best flavour but they tend to spoil the colour of the soup, making it very dark. Oyster mushrooms
• can also be used.