Canh chua is a Vietnamese sour soup native to Southern Vietnam, and water mimosa (Neptunia oleracea, Vietnamese: rau nhút or rau rút) is a highly prized vegetable. The sour soup with water mimosa (Vietnamese: canh chua rau nhút) is a common family dish, and is often cooked with shrimps, paddy crabs, sneakhead fish or climbing perch fish (Anabas testudineus).
Squeeze the tamarind jam or paste with a spoon in a hot water bowl, then strain it to get the tamarind juice. If you use fresh tamarind fruits, cook them first.
Heat the oil in a soup pot and add crushed shrimps to stir-fry. Pour 4-5 bowls of water (about 4 -4 ½ US cups), and bring to boil. Add water mimosa, then the tamarind juice into the soup pot. Once the water mimosa becomes translucent, add tomatoes wedges, bring to a boil and turn off the heat. Season the soup with salt, sugar, fish sauce, and MSG or granule seasoning to suit your taste buds.
Pour the soup into a serving bowl, dredge paddy herbs, and sliced chillis.
To add the sweet taste, you can use a few pineapple slices.
If you don't have tamarind, you can use starfruit or fermented rice.