Wash, shell and de-vein the prawns, leaving the tail on.
In a wok heat 1 cup of coconut milk over medium heat until the oil surfaces, add the curry paste, stir constantly for 2 minutes until fragrant. Gradually add the remining coconut milk. When the mixture starts boiling, add the prawns and cook until done (when they turn pink).
Season to taste with fish sauce and sugar, stir lightly to combine. Then turn off the heat.
Transfer to a serving dish, garnish with shredded kaffir lime leaves, red chillies and sweet basil leaves. Serve with steamed Thai jasmine rice.