Spice Paste: In a food processor or with a mortar and pestle, blend the spice paste ingredients together. Set aside
Curry: In a large wok heat 1 tablespoon oil. Fry the onions until fragrant then add the spice paste. Fry until fragrant and the paste turns a few shades darker.
Add the curry leaves, cinnamon stick, star anise and cloves then fry for a few minutes before adding the chicken. Coat the chicken pieces with the spice paste and cook until lightly browned to seal in the juices.
Add the water and potatoes and simmer until the chicken is cooked through and the potatoes are done.
Add soy sauce and tomatoes then cook for another 5 minutes. Serve hot with rice or French bread.