Method:

1. Pound peppercorns, turmeric, ginger, chopped garlic, juice and coriander roots to a rough paste using a mortar and pestle (or small processor).
2. Score fish on both sides at 1cm intervals, then rub in paste.
3. Invert 2 small heat proof plates in the base of a fish kettle or a large flameproof roasting pan.
4. Pour about 2.5cm of boiling water into the fish kettle (you’ll need to place it over 2 burners).
5. Bring to a simmer over medium heat. Place fish on the kettle rack and lower onto plates, ensuring fish isn’t touching water.
6. Cover with a lid or
 foil and cook for 20-25 minutes, depending on size of the fish (topping up the water if necessary) until cooked through. Carefully remove fish and place on a long platter.
7. Meanwhile, half-fill a small heavy-based saucepan with oil and heat to 190°c (a cube of bread will turn golden in 30 seconds when hot). Add onion and fry for 1-2 minutes until golden, then remove with a slotted spoon and drain on a paper towel.
8. Repeat with sliced garlic for 20 seconds until golden, then with chilli and curry leaves for 30 seconds until crisp. carefully place the fish on a platter, top with fried ingredients and 2tbsp of the hot oil, then serve with lime.