Preparation

1. Prepare the marinade: peel and chop the ginger. Also chop the lemongrass stalks and chili pepper. Blend the lemongrass, garlic and ginger in a food processor, then add the juice of 1 lime and the olive oil. Remove a third of the mixture, add the chopped green chilli and set aside. Put the rest of the mixture in a small bowl and add the prawns. Leave to marinate for around 30 min. Remove the prawns and discard the marinade.

2. Preheat oven to 200°C (gas mark 7). In a bowl, mix the coarse salt with 3-4 tablespoons of water. Line a pie dish with some of this mixture, then place the prawns on top, heads facing outwards. Cover with the rest of the wet salt, leaving the heads uncovered. Place in the oven for 8 to 10 min. The prawns are cooked when the heads are brown.

3. Remove the top layer of salt with a fork. Quarter the 2nd lime. Serve with the well-infused lemongrass-ginger-chilli sauce and lemon pieces.