Fresh longan ("dragon eye") is a delicious, sweet, succulent fruit. When dried, however, the fruit transforms into something shrivelled, dark and chewy, with a rich, smoky flavour. It can be eaten out of hand (like raisins or dried cranberries) but more often it's used for making tong sui (sweet soups) and in traditional Chinese medicine (TCM).
Like the fresh fruit, dried longan is considered heating, so it should be consumed in moderation; too much can cause insomnia, coughs and nosebleeds. Because of its heating qualities, it's brewed into tonic teas for women who have just given birth and is fed to the elderly. Dried longan is often cooked with bitter medicinal herbs and spices because the fruit's sweetness makes the other ingredients more palatable.
In TCM, dried longan is prescribed for those who are anaemic and is believed to strengthen the qi, heart and spleen, alleviate tiredness and enrich the blood.
For a delicious, sweet and mild tonic soup that is supposed to strengthen the body and make your skin more beautiful, rinse then soak dried longans with Chinese red dates and a small amount of white fungus. Simmer the ingredients until tender, then add some rock sugar to taste. Serve it hot or cold.