wash and drain chicken thoroughly. Apply salt and half of each termeric, red chilli, coriander-cumin poder to it and keep aside. Grind pudina, coriander, ginger and garlic together and make a fine paste. apply half of the paste to chicken. Now heat oil in a pan and add chopped onions just saute a little and and ground green masala. when oil starts separating from masala, Grind tomatoes, make a fine paste and fry with onions. add remaining turmeric, redchili, coriander-cumin powder. and salt if u think it is required (remember u have already applied salt to chicken) when u start getting lovely aroma of masala, add chicken (and potatoes if u like) and cover it. cook it on a slow flame. as chicken is getting cooked, it leaves water so you dont need to add extra water. when chicken is done, add coconut milk and garam masala powder and turn off the fire in next 5 minutes. chicken curry is ready.