1.Heat oil in a deep vessel.
2.Add the tempering mustard,cumin.
3.After it splutters add whole garam masala.
4.Add chopped onions and saute until golden brown.
5.Add salt, turmeric powder, ginger garlic paste,green chillies andcurry leaves.
6.Saute everything for 5 mins.
7.Add tomatoes and saute it until it becomes a gravy.
8.Add chilli powder,coriander  powder,cumin powder.
9.Saute everything for 10 mins in medium heat.
10.When oil comes out its the correct consistency
11.Now add chicken, little water and cover and cook.
12.After its cooked add the crushed pepper powder and check for seasoning.
13.To garnish add chopped corriander leaves. You can also add chunks of capsicum.