The goji berry, which goes by many names - including wolfberry, kei chi and red medlar berry - has long been used in traditional Chinese medicine. More recently, though, it's been hailed by Western nutritionists as a miracle fruit, joining others such as the pomegranate and the blueberry.
This tiny reddish berry aids the immune system, slows down ageing, boosts sexual prowess and improves eyesight, is it believed, and it is also valued for its antioxidants and essential vitamins and minerals.
When fresh, goji berries are small, plump, oval-shaped and glossy red; when dried (which is how most of them are available), they're shrivelled, and have a dull red colour. The most convenient and inexpensive way to buy them is from shops selling dried Chinese fruits, herbs and nuts, although they're also sold in small packets at high prices in upscale supermarkets. They have seeds inside and a sweet, slightly bitter flavour.
The simplest way to prepare them is to make an infusion that's drunk like tea: put the berries in a teapot, cover with hot water and let them steep.
They're also used in many Chinese soups: in some versions of bak kut teh (a pork bone "tea" that's eaten in Malaysia, Singapore and Taiwan); simmered with an old (and therefore tough but flavourful) chicken, ginseng and red dates; or cooked with turtle and bitter herbs. Goji berries can also be steamed with fish or tofu, and add a subtle sweetness to braised chicken and pork dishes.