Cá lăng or Bagrid catfish (Hemibagrus guttatus) is a wild species of catfish which lives in mountainous brooks, waterfalls or rapids. Legend has it that cá lăng fish are the largest freshwater fish in Vietnam, and wild-caught ones may weight up to nearly 100 kilograms (220 pounds). However, the fish is endangered due to overhunting, and now it has been farm-raised in some rivers.
Cá lăng fish is highly prized in Vietnam for its firm and boneless meat texture. It’s the main ingredient for a well-known Hanoi dish called chả cá Lã Vọng. In Phú Thọ province, there are also restaurants that sell only dishes made from this kind of fish.
Cá lăng xốt cà ri, which can be translated as (fried) bagrid catfish with curry sauce, is introduced by Chef Trần Ngọc Nghĩa. He also paires fried bagrid catfish with crispy-fried grapefruit zest.
The final dish will bring out the sweetness of the fish flesh, the lingering cool effect of the grapefruit zest, and the mild spiciness of the curry sauce.
For the bagrid catfish: Dry the fish fillets with a kitchen towel and cut into 4 portions. Juice the garlic cloves. Rub and squeeze the grapfruit zest with salt and rinse under cold water 5 or 6 times to reduce the menthol taste of the zest. Later, do the same with the zest and potash alum, and rinse and squeeze the zest dry. Cut the zest in to 5-cm (1.96 inch) stripes and marinated with 2 grams (about 1/2 teaspoon) of granulated sugar. For the sauce: Cut lemongrass stalkss into 5-cm (1.96 inch) pieces, and get them crushed. Peel the garlice cloves and crush. Remove the stems of bird's eye chilis and then crush as well, then mix all sauce ingredients with 5ml (1 teaspoon) of water.
Marinate the fish fillets with garlic juice, granule seasoning (4 grams), black pepper (1 gram), egg liquid (1 egg) for 15 minutes. Dissolve the crispy flour (50 grams) into water (60 ml) and whisked egg liquid (1 egg). Let the batter rest for 10 minutes. Pour the remaining crispy flour into a plate.
Heat the oil to medium heat, dredge the grapefruit zest stripes into the crispy flour liquid, then slowly add the zest stripes in to the hot oil until they turn golden brown. After finishing, remove the excess batter in the oil, and start frying the fish fillets. This time, dredge the fish fillets into the dry crispy flour, shaking off any excess, and then fry until they are golden from both sides.
Pour oil into a hot pan, then add annatto oil, crushed lemongrass, chilis, and garlic to sauté. Next, add curry powder then stir quickly. Finally, add coconut milk and bring the liquid to the boil, reduce the heat and cook for another 5 minutes then add granulated sugar (8 grams), granule seasoning (4 grams), and salt (2 grams). Taste the liquid if it suits your palate and add tapioca starch the thicken the sauce.
Place the fish fillets on a deep plate. Warm the curry sauce and pour onto the fillets. Server the dish with grapefruit zest fries and some coriander leaves.
Pre-cook the sauce first. When the dish is about to be served, fry the fish fillets and warm the sauce to serve.
Cook the curry sauce on low heat to retain its flavor.