All in all, this should take about 3 hours (or 1 if using a pressure cooker).
Toast all the whole spices until fragrant, remove to a bowl and grind finely once they are cool.
Note on heat level: regular Indian chilli powder is pretty hot. Using a tbsp of chilli powder makes it slightly too spicy even without adding fresh chillies. Consider using sweet paprika to replace some of the chilli powder and then add fresh chillies if wanted.
Finely chop the onions and fry them in some ghee and oil. Mince the garlic, finely grate the ginger, remove the stem of the chillies and add them to the onions. Add also the curry leaves. Cook until the raw smell is gone. Add the pieces of lamb, chilli powder, coriander powder and turmeric. Fry until the lamb changes color and starts to release its liquid. Add enough water to just barely cover the lamb and simmer until well cooked (1-2 hours) and the liquid is reduced to a sauce. When it’s close to done, add the ground spice mix.
Once completly cooked, add also the vinegar and boil 1-2 minutes. Take off the heat and sprinkle with chopped cilantro.
Serve with plain rice and raita, and maybe a simple salad.
Add the spice mix with the onion. Let the onion and spice mix cool, then puree and set aside.
Fry the lamb with a little extra ghee and oil, add the spices and enough water to cover it, then cook it until done. This can be done in a pressure cooker to save time.
Once the lamb is cooked, heat a little more ghee and oil, add the sauce set aside and bring it back to boiling. Add also the lamb with all its liquid and bring to a boil, then add the vinegar and finish off with chopped cilantro.