- Season both sides of the fish fillets with salt and pepper. Dust both sides with flour and dust off the excess.
- Heat 3 tbsp oil over high heat in a large non-stick pan. Carefully place fish fillets into hot oil and fry until lightly browned on both sides. Dish out and set aside.
- Add in 1 tbsp oil, turn the flame to medium heat and sauté shallots and spring onions until softened, about 3 mins. Stir in garlic and chillies and cook for another 1 min until fragrant.
- Toss in tomatoes and cook for about 5 mins until softened. Stir in mustard greens and pour in chicken stock. Carefully place fish fillets into the broth and increase the heat to medium high heat. Cook and baste the fish fillets for about 8 mins until the fish fillets are just cooked through.
- Mix in fish sauce until well combined. Transfer to a serving plate and garnish with fresh coriander and fried shallots. Serve with steamed rice.