Goraka

Also known as Malabar tamarind, this is a small sour fruit, usually used in dried form. Sinhalese recipes often use a clove of goraka to give a tangy flavour and to thicken curries (where Tamil recipes would use tamarind). But if you can’t find it you can just add lime juice to the dish at the end. One recipe calls for goraka paste, which you may find in Asian grocers or online, but this can easily be substituted with the more widely available tamarind paste.