Put the meat into a bowl and add the ginger, garlic, cumin, turmeric and most of the salt. Mix well and set aside for 30 minutes.
When ready to cook pour the oil into a wide non stick lidded pan and set over a medium high heat. When hot stir in the onions and fry until the pieces turn brown at the edges.
Add the meat together with its marinade. Stir and fry for one minute. Cover, reduce the heat to medium low and cook for 8-10 minutes, stirring occasionally, until the meat is lightly browned.
Stir in the tomatoes, the remaining salt, chillies, curry leaves and coriander and bring to a simmer. Cover, reduce the heat to very low and cook gently for about 50 minutes, stirring occasionally , until the lamb is tender.