- Cut lamb into small pieces. 
- Marinate it with oil, vinegar, tamarind and salt at room temperature for 5 hrs. 
- Put 2 tbsp of oil, onion, garlic and ginger in a food processor or blender and run the machine, until a fine pasty puree is formed. 
- Heat 1/2 cup oil in large skillet on a medium-high flame. 
- Add onions and saute, until they are caramel brown, stirring constantly to avoid burning. 
- Add the puree. 
- Reduce the heat. 
- Add cumin, mustard, turmeric, red  pepper, paprika and cinnamon. 
- When the spices begin to sizzle and turn dark(about 15 seconds), add the lamb and bones(without the marinade). 
- :- Reserve the marinade. 
- Cook, until slightly seared for about 10 mins. 
- Add water to the marinade to make 2 1/2 cups of liquid. 
- Add it into the pan and bring to a boil. 
- Lower the heat and simmer, partially covered, until meat is very tender for about 30 mins.