Ingredients:
3 lbs boneless lamb
1/4 Cup vegetable oil
1/4 Cup cider vinegar
3 Tablespoons tamarind pulp
Salt to taste
2 Tablespoons vegetable oil
1 Big white onion
6 Garlic cloves
2 Tablespoons fresh ginger root
1/4 Cup vegetable oil
2 Cups onions, thinly sliced
1 Teaspoon ground cumin
1 Teaspoon ground mustard
3 Teaspoons turmeric
1 1/2 Teaspoons red (cayenne) pepper
1/2 Teaspoon chili flakes (or more)
3 Teaspoons paprika
1 Teaspoon ground cinnamon (optional)
1 Can tomato paste
1 Cup tomatoes, roughly chopped
Hot water (to cover)

Method:
1. Cut lamb into 3/4″ cubes. Place lamb and the bones in a non-metallic bowl (or ziplock bag) with the oil, vinegar, tamarind and salt. Marinade at room temperature for 8 hours, or refrigerated for at least 24 hours.
Put two tablespoons oil, onion, garlic and ginger in a food processor and puree.
2. Heat 1/4 cup oil in large skillet (or oven-safe pot) over medium-high heat.
3. Add onions and saute until brown, stirring constantly to avoid burning. Add the puree.
4. Reduce 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, reserving the marinade.
5. Cook until slightly seared (about 10 minutes).
6. Add tomato paste and cook slightly, stirring constantly to avoid burning.
7. Add (hot) water to the marinade to make 2 1/2 cups liquid; add to pan and bring to a boil, add tomatoes, then lower the heat and simmer, covered (about 45 minutes) or place, covered in preheated 350* oven for (30 – 45 minutes), until meat is very tender and vegetables are dissolved into the sauce.
8. Remove from heat. Allow to stand 10 – 15 minutes
Serve with rice and naan