Canh chua

Canh chua is a Vietnamese sour soup indigenous to the Mekong Delta region of Southern Vietnam (Central Vietnam also have their own canh chua). It is typically made with fish from the Mekong River Delta, pineapple, tomatoes (and sometimes also other vegetables such as đậu bắp or dọc mùng), and bean sprouts, in a tamarind-flavored broth. It is garnished with the lemony-scented herb ngò gai (Limnophila aromatica), caramelized garlic, and chopped scallions, as well as other herbs, according to the specific variety of canh chua; these other herbs may include rau răm (Vietnamese coriander), ngò om (long coriander), and rau quế (Thai basil). It can be served alone, with white rice, or with rice vermicelli. Variations can include prawns, squid, spare ribs, fish cakes and quail eggs. The sour taste of the soup comes from tamarind, which is mixed with a small amount of hot water; the mixture is then stirred for a few moments to release all the essence, and the liquid (minus the tamarind seeds and other solids, which are discarded) is then added to the soup. When made in style of a hot pot, canh chua is called lẩu canh chua.

Source: Wikipedia