Place the oil, sliced lemongrass, sliced ginger and peppercorns in a small pot. Heat on a medium heat until the oil starts to bubble and then turn off. Leave to cool and steep while you prepare the fish.
Slice each side of the fish down to the bone 5-6 times on a diagonal. Slice one of the limes into 5mm slices. Heat your pan, oven or BBQ to a medium heat. Place the lime slices down and then the fish on top. Drain the oil mixture so there are no bits left. Baste the fish with one third of the oil mixture. Cook for 10 minutes covered and then turn the fish over. Baste with another third of the oil mixture and cover. Cook for a further 10 minutes and then increase the heat. Cook both sides of the fish so that the skin becomes a little crisp.
Prepare your serving plate with some sliced lime. Place the fish in the middle and use the cooked lime to cover the face and eye. Drizzle the last of the oil mixture over the fish. Serve with a fresh garden salad.
