Heat oil in a cooking vessel, add the onions and saute till pink. Add the green chillis, ginger-garlic paste and saute further for another 4-5 mts on medium heat.
Add the cleaned chicken pieces and cook on high heat for 4-5 mts, combining once in a while.
Add the turmeric pwd, coriander pwd, fennel seed pwd, pepper pwd and salt, combine well.
Reduce heat to medium, cook covered for another 4-5 mts.
Add the chopped tomatoes and let it cook for 3-4 minutes without cover. Combine well and cook till oil separates.
Let the chicken cook in its own water, covered for 4-5 mts. Add half a cup of water and cook covered for another 4-5 mts or till you get the desired gravy consistency.
Finally add the garam masala pwd, combine well and garnish with fresh coriander leaves.
Serve hot with white steamed rice or chapatis.