- Combine the soy sauce, sesame oil and Chinese rice wine or sherry in a bowl. Add the strips of beef and toss until well mixed. Leave to marinate until needed.
- Heat the stock in a large pan or flame-proof casserole. Add the spring onions, sliced mushrooms and halved pak choi, and simmer for 2 minutes.
- Add the nests of noodles to the pan of vegetables and cook for 2-4 minutes or until tender.
- While the noodles are cooking, heat a wok or frying pan with the oil and stir-fry the beef for 2 minutes or until browned. Tip the contents of the pan into the simmering stock. Bring back to the boil. Taste and season with black pepper, then ladle into four serving bowls and serve.
For beef, use chicken breast fillets. Replace the stock with chicken stock.
Dried shiitake mushrooms are useful to keep in the storecupboard, but you will need time to soak them before they can be added to a recipe. Soak in water for about 3 minutes, then rinse to remove any grit. Soak in warm water for a further 30 minutes to soften. Cut off the stalks and discard, then continue as for fresh shiitake. (The soaking liquid can be strained and added to the stock.)