1. Grind togeather green chillies, ginger, mustard, coriander leaves and salt.
2. Clean and cut fish, Wash well.
3. Smear fish with ground ingredients.
4. Heat a little fat. Fry fish lightly. Remove.
5. Add morenbsp;fat and remaining spice. Mix well.
6. Put fish in a pan, pour over the fat and spices, thick coconut milk and tomato sauce.
7. Add butter and allow to cook until tender.
8. Serve hot, garnished with peas or fried potatoes.