For Tamarind Sauce
Combine all ingredients in a small saucepan, stir until sugar is completely dissolved. Place over medium low heat until boiling, keep stirring. Simmer for further few minutes until the sauce thickens. Set aside.
To Cook
Clean the whole prawns, cut at the back from head to tail and devein.
Grill the prawns for few minutes, or only just cooked.
Arrange the prawns in a serving plate.
Pour the tamarind sauce over the prawns.
Garnish with fried shallot and dried chilli.