1) In a small bowl make a marinade by mixing the lemon juice, turmeric powder and chilli powder. Marinate the mutton pieces and refrigerate for an hour covered.
2) Finely chop the garlic, chillies and ginger, keep aside.
3) Finely chop 3 of the onions and roughly chop the rest of the onions.
4) Heat the oil in a heavy bottomed pan. Add the cumin seeds and curry leaves and fry until they start to crackle.
5) Add and sauté the finely chopped onions till they are golden brown.
6) Add the mutton pieces and sauté along with the onions. Add the ghee, ginger, garlic, garam masala, coriander powder, chillies and salt.
7) Fry for a few minutes.
8) Add the remaining onions and enough water to just cover.
9) Cook on medium high flame for 10-15 minutes.
10) Add more water if necessary then reduce the heat to a simmer, cover with a lid and cook for 1 hour or till the mutton is tender. Stirring occasionally.
11) Garnish with the chopped coriander.
12) Serve hot with roti or rice.