In a bowl, whisk the yoghurt with all the other ingredients for the marinade, add the chicken pieces and mix well to coat all pieces. Cover and refrigerate overnight.
Using a little water, grind all the masala ingredients into a thick, smooth paste.
Heat the ghee in a wide, heavy-based pan, with the flame on medium, remove the chicken pieces from the marinade and add to the pan. Reserve the rest of the marinade. Sear and lightly brown the chicken.
Now add the rest of the marinade and the green masala. Mix well and cook the chicken covered for 20 minutes without adding water (the chicken will cook in its own juices), stirring once or twice.
Once the chicken is cooked and the gravy is thick, add very little water if / as required and correct the seasoning and cook for a minute more. The gravy should coat the chicken. Serve, garnished with almond slivers.