Place a pan on medium heat and add oil
Add onion, garlic, curry leaves, chilli, lemongrass, pandan leaves and cook well until the onions are soft, then add the curry powder, chilli powder, salt and mix well cook for about 1 minute, then add the marinated chicken.
Add water until the chicken is well submerged in the liquid, close lid and cook for about 30 minutes ( Make sure that the fire is on low heat and check the curry time to time, to see if the water has evaporated, then add more water and keep cooking)
After 30 minutes add the tomatoes, thick coconut milk, and if using tamarind, then add the tamarind at this point. ( At this point check the seasoning, by tatsing the curry, if it needs more salt, then add more)
Cover with a lid and cook for further 15 minutes or until the chicken is fully cooked and succulent. If it doesn't have enough liquid or curry gravy add more water.
Turn off the fire and add lime juice to balance the seasoning of the whole dish
Serve with hot rice