White chicken curry ( Chicken Rezala)

This recipe belongs to my mother... Chicken rezala is very popular in eastern part of India.

Ingredients:
500gms diced boneless Chicken
3/4 cup unsweetened yoghurt
4 medium sized onion
1tbsp ginger garlic paste
2 cardamom pods
2-3 Green chillies
2tbsp clarified butter or oil
Salt to taste
1tsp sugar

Garam masala :
1" Cinnamon stick
1/2 anistar
2 cloves
6-8 pepercorns
2 bayleaves
A pinch of nutmeg powder
1tsp cumin seeds

Method:

Marinade the chicken pieces in ginger-garlic paste and yoghurt for an hour.
Dry roast the garam masala spices in a wok,then grind into fine powder.
Chop half of the required onion in round slices and the other half into a coarse paste.
Heat Oil/clarified butter in a heavy bottomed pan.Add onion paste and fry till the onion just starts to change colour. Add onion slices ,fry for a minute, then add the marinated chicken with the marinade.
Fry in high flame for a minute stirring continuously.Add the garam masala spice mix , salt and sugar. Fry for another couple of minutes.
Simmer the heat ,cover the pan with a lid and let the chicken cook till tender.
Add green chillies.Cook for 2-3 minutes more till oil starts to separate.
Serve hot with rice, pulao ,chapatti or paratha.