Prawns: In a saucepan, heat one litre of water over medium heat with the salt, pepper, bouquet garni, onion, carrot and chilli. Add the prawns and cook for 4 minutes. Drain and pour into a large bowl.
Sauce: In a bowl mix the garlic, onion, carrot, cucumber, capsicum, lime juice, allspice grains and cloves. Stir in the cooked prawns then add the annatto oil and stir well. Marinate overnight in the refrigerator.
Serve chilled with small boiled potatoes or sweet potatoes.