"Three treasures of the earth" – aubergine, potato and pepper (Di san xian)

1. Cut the aubergine and peeled potatoes into 3 cm irregular chunks and the green pepper into larger squares; sprinkle the aubergine with 1 tablespoon of cornflour.

2. For the sauce, mix the soy sauce, oyster sauce, sugar, salt, the remaining cornflour and the water; finely chop the garlic and slice the spring onion.

3. Heat the oil in the wok and fry the potatoes for 6-8 minutes until golden and cooked through; lift out.

4. In the same oil fry the aubergine for 4-5 minutes until golden and soft, adding the pepper for the last 30 seconds; lift out and pour off most of the oil.

5. In the remaining oil fry the garlic and spring onion for 20 seconds, pour in the sauce and bring to the boil until thickened.

6. Return the vegetables, toss for 30 seconds until glossily coated, and serve with rice.

Tip: A popular home-style dish from north-east China (Manchuria), made from three cheap summer vegetables. To use less oil, you can roast the potatoes and aubergine brushed with a little oil at 200 °C.