Ingredients:
3 Roasted baray pai (cow's trotters)
2 kg. bone with marrow
4 kg. bong (shank)
Ingredients For Stock
3 medium onions, skinned and roughly chop
3 garlic bulbs, skinned and ground
2 inch piece ginger peeled and ground
1 inch cinnamon stick
12 cloves
1 tbsp. whole black pepper
6 black cardamoms
4 liter water
Ingredients For Gravy
4 onions skinned and thinly sliced
3 tbsp. ground garlic
2 tbsp. ground ginger
2 tbsp. coriander powder
2tbsp. chili powder
2 tbsp. garam masala
12 tsp. turmeric powder
2 cups oil 

Method:

1. If roasted pias are not available. Roast them over open gas flame. There is a bunch of hair between the hooves. With a sharp knife make a long cut between the hoff and carefully remove hair.
2. Wash the pai thoroughly under running tap and scratch any burnt part with a sharp knife. 
3. Place pai and all the ingredients for stock in a large heavy based sauce pan. Bring to boil, reduce the heat, cover and allow to boil gently for about 3-4 hours until the meat is almost tender. (The process can be speeded up in a pressure cooker. Use half the quantity of water. Follow the manufacturer's instructions for timing. note: It will take at least 1 12 hours in a pressure cooker.) 
4. Meanwhile prepare the gravy. Heat oil in a large heavy based pan and add sliced onions. String frequently fry for 5-8 minutes until the onions are transparent and soft but not brown. Add the garlic and ginger paste and continue frying for another few minutes. Add a little stock to prevent the mixture from sticking to the bottom. Add the turmeric, chili powder, coriander powder, garam masala and salt. Stir fry for another few minutes. Add a little more stock if the mixture sticks to the bottom of the pan. 
5. Remove pais from the stock and add to the gravy. Add 12 cup stock and stirring frequently fry for 10 -12 minutes. Add little more stock to prevent the mixture from sticking. Turn off the fire, carefully remove the pai from the gravy, and put them back in the stock. Place it over medium flame and bring to boil, reduce the heat to low. Cover and cook until the pai are very tender and soft and about 8-10 cups of soup is left.
6. Reheat the gravy, add meat to it and stirring frequently fry for 12-15 until the meat is well browned. Add little water if while frying meat stick to the bottom of the pan. Add 4 cups of water to the meat, cover and cook over low heat (stirring occasionally) until the meat is tender and oil begins to separate from the gravy. Turn off the fire.
7. When the pais are very tender and soft, add beef mixture to it. Carefully stir once and cook for another 5 minutes. Don't over stir otherwise the meat pieces will break. Serve hot with Nan or boiled rice.