Clean, shell and devein the prawns. Wash them thoroughly and dry them.
Heat the coconut milk, the lemon grass, cinnamon and cloves in a small non-stick saucepan. Bring it to a boil and continue to simmer for 10 minutes on low heat until slightly thickened, stirring occasionally.
Heat the oil in a large wok. Add the turmeric powder and fry for just a few seconds, until it turns a little darker. Add a tablespoonful of water. When it starts sizzling, add the garlic and stir-fry for half a minute. Add the onions and red chiles and fry well.
Add the prawns and keep on stirring until they turn pink. Add the curry leaves and transfer this mixture to the saucepan.