1. Heat the oil in a deep pan or saucepan and fry the chicken cubes in batches until brown. Remove and set aside.
2. In the same pan, fry the onion, garlic, lemongrass and curry leaves until soft. Add the chilli powder, ground coriander, turmeric, curry powder and cinnamon stick, and stir-fry until fragrant.
3. Stir in the tomatoes and coconut milk or yoghurt and bring to the boil. Return the chicken to the pan or saucepan and simmer to heat through. Add the maizena paste and stir over medium heat until the curry thickens slightly.