In a large pan, combine water and all the spices (curry powder, salt, black pepper, crushed red pepper, sugar).

Stir until well mixed.

Add the chicken pieces and diced onion to the pan.

If using lemon grass, add it to the pan as well.

Cook over high heat until the mixture comes to a boil, then reduce the heat to medium.

Stir well to ensure the chicken is evenly coated with the sauce.

Cover and simmer for approximately 30-40 minutes, or until the sauce has thickened, and the chicken is well-cooked.

Stir the curry chicken every 10 minutes during cooking to ensure even coating with the sauce.

If a thinner sauce is desired, more water can be added during cooking.

Serve hot with steamed rice.