The bhuna style gives a quite dry sauce that clings to the meat rather than the meat swimming in gravy.
For the spice mix
Add all spice mix ingredients to a hot, dry frying pan and toast them for a few minutes. Remove from heat and grind them to a powder in a spice mill or coffee grinder.
For the sauce
Thinly slice and chop the onions, crush/mince the garlic and ginger. Heat a generous amount of ghee in a frying pan, and cook the onions, garlic and ginger for about five minutes until the onions are translucent but not browned. Chop the tomatoes and add them to the pan. Add the curry leaves. Stir ocasionally until the sauce has reduced and thickened a little. Add the spice mix you made earlier and stir it in.
Add the cubes of lamb, and enough water to just cover everything. Bring to the boil, and then cover and simmer for about an hour and half, stirring occasionally to make sure nothing is sticking. By now, the meat should be very tender. Turn up the heat and reduce the sauce to almost nothing. You need to stir it constantly during this stage.
For the garnish
Thinly slice half a small onion (try to keep it as rings) and fry in some ghee until caramelised. Chop some fresh coriander (cilantro).
Place a dome of pilau rice on a plate with some bhuna around it, and top with onion rings and coriander.