1/Mix the natural yoghurt, turmeric powder, chilli powder, garam masala and salt together and add the lamb. Cover and set aside to marinade for 10 minutes
2/Heat a heavy bottomed pan and caramelise the sugar, until golden brown.
3/Add the oil and, when hot, add the drained lamb cubes, reserving the marinade
4/Brown the meat and add the onions. Stir and cook until caramelised.
5/ Add the ginger garlic paste and tomato puree followed by the potatoes and the marinade.
6/Pour in 150 ml boiling water and cook for approximately 40 minutes, or until the meat and potatoes are tender. (Add more water if necessary while cooking if the curry gets too dry).