I made this for some friends and they were licking the bones, literally! It's quick and easy as long as you get your fishmonger to scale and clean the fish – it will be on the table in no time.
Preheat oven to 180. Take a large sheet of foil and drizzle the base with olive oil so the fish doesn't stick. Take a kitchen knife and make 3 incisions across the fillet and another 3 in the opposite direction, season with S&P inside the cavity as well as the skin. Chop off the root of the coriander and place in the cavity. Place fish on the foil and place another piece on top and fold edges to create an envelope. Put in the oven for 35-40 minutes or until cooked through.
To make the dressing, add the coconut milk, lemongrass, chilli, sugar and fish sauce in a saucepan and bring to the boil. Turn the heat down and allow it to simmer for 10minutes. Finish with the lime juice.
When the fish is cooked transfer to a large serving plate and strain dressing over the top of the fish. Finish with chopped coriander and fresh lime, serve with rice.