Tamarind concentrate 罗望子酱 (luó wàng zˇı jiàng)

A thick, dark brown sauce made from the fruit of a tree native to Asia, it has a sweet and sour flavor and is used in Southeast Asian, Indian, and Macanese cooking. If you cannot find the concentrate form of the fruit at a
specialty grocery store or Indian market, you can buy tamarind pulp at an Indian or Spanish market, soak it in
warm water, and then strain the juice and discard any bit of shell and fibers.