Heat oil and fry onions till brown. Drain them in colander and once dry, crush with your hands. Set aside.
Place the green chilies and coriander in a blender and pulse till a paste is formed. Alternatively, put them in a mortar and pestle and just bash a few times till a thick paste is formed. Add water if required. Set aside.
Heat about 2 tablespoons of the leftover oil from frying the onions, and add ginger garlic paste followed by the chicken.
Cook the chicken till golden, and then add green chili paste and yoghurt. Add salt, roasted cumin powder and black pepper.
Stir together and cook on low heat till the chicken is cooked through, and then add the crushed onions.
Finally add cream, and mix. Take off heat and serve hot with paratha or roti.
Garnish with sliced green chilies and more roasted cumin powder.