Bring 1 litre of water with the chicken thighs to the boil. Turn down the heat and simmer for 15 minutes.
Meanwhile, open the coconut by poking out the holes in 2 of the 3 eyes, or indentations, at the base of the nut. Collect the coconut water in a glass. Tap the coconut carefully with the hammer until the shell starts to crack. Break it open and cut the coconut meat away from the shell. Grate the coconut meat.
Chop the onion and finely chop the garlic. Peel and finely slice the ginger. Finely slice the rawit peppers. Slice the lemongrass stalks into 3 pieces.
Remove the chicken from the cooking liquid. Heat 2 tablespoons of coconut oil in a soup pan. Stir fry the onion, garlic, rawit peppers, ginger, lemongrass and the grated coconut for 3 minutes on a medium heat. Add the tomato purée, fry for 2 minutes. Then add the cooking liquid, coconut milk and stock cube. Bring to the boil then leave the mixture to simmer gently for 10 minutes.
Meanwhile, cut the carrot into fine strips, the leek into thin half rings and the cooked chicken thigh into strips.
Remove the lemongrass from the soup. Purée the soup with the blender. Season the soup with the ketjap, brown sugar and salt. Add the chicken and the prawns.
Heat the rest of the coconut oil in the wok and stir fry the carrot, leek and bean sprouts on a high heat for 2 minutes. Divide the soup over 4 bowls and divide the vegetables over the bowls.
