Pangasius krempfi (Vietnamese: cá bông lau) is a unique catfish among Pangasiidae species in the Mekong River basin, which spends a major part of its life in marine coastal waters. In Vietnam, bông lau fish is praised as the most delicious fish in the Pangasius family. Its cooked flesh has a delicious, sweet and delicate taste, which turns the fish into a delicacy food of the region. Like other catfish, bông lau fish is fatty, home cooks often make canh chua dish, a Vietnamese sour soup, braised fish dish and fried fillets.
Roselle plant (Hibiscus sabdariffa, Vietnamese: cây bụp giấm or cây giấm) can be found in Vietnamese cuisine as a source of acidity because both its fruits and leaves have sour taste. They are often cooked with some fish or aquatic food in canh chua . Its fruits have a shape like an Asian shallot bulb, a fine hairy crimson skin with many layers surrounding the seed pocket like a calyx. Its leaves is called lá bụp giấm or simply lá giấm, and have a pale green color, and is more commonly found than its fruits.
According to local folks, canh chua soup with roselle leaves is very suitable to pair with shrimps, especially catfish like catfish. In rural or mountainous areas, people often pick young roselle leaves and fruits to make braised fish dish, as a “medicinal dish”.
Bring a pot of water to a boil. Put roselle leaves and fruits into the pot. Add fish sauce, sugar, granule seasoning to suit your taste buds. If the soup is not sour enough, add more leaves.
Add fish chunks, and chilli slices and some extra vegetables like tomato wedges, sliced morning glory, okra slices,...
Serve the soup with rice or bún noodle.
When made into a hotpot dish, the broth should be cooked with pig shank bones and the fish head.