Heat oil in a dutch oven or large cooking pot over medium heat.
Add whole spices and whole green chili (optional). Let splutter a few moments, and then add onions.
Sauté till onions are nearly ¾brown. Approximately 8 minutes.
Add the chicken. Sauté well until the chicken is nicely glazed, approximately 10 minutes.
Add the ginger, garlic, and spice powders. Continue to sauté for about 8 minutes.
Now add half of the chopped cilantro and continue to cook, frequently stirring until most of the moisture is absorbed. You can tell when, as the oil starts to appear on the sides of the pan. About 10 minutes more.
Add the hot water, stock (add more water if you do not have stock), potatoes, and tomato paste. Cover and let cook until the potatoes are done. Approximately 15 minutes.
Serve in a deep dish and garnish with the remaining cilantro.