When the oil is hot, add the meat, 1 tbsp nihari masala, 1 tbsp ginger-garlic paste, cumin, coriander, garam masala and paprika powder. Add tomato puree and salt.
Fry the meat and all the masalas for 10 minutes. Add 3-4 glasses of water and let it cook till the meat is tender.
Keep the cooked meat and gravy aside.
In another large pot, heat the remaining oil and add sliced onion and fry it till golden brown.
Add a large tbsp of nihari masala and fry it for a minute.
Add the meat and gravy to the large pot.
Add 5-6 tbsp of wheat flour in a bowl and mix it into a smooth paste with some water. Add it to the meat and onion gravy. Add some water (adjust the quantity of the wheat flour depending on the desired thickness of the gravy) and let it cook on medium heat for about 20 minutes till the flour is cooked.
Reduce the heat, cover the pot and let it cook for another 10 minutes till the oil floats to the top.
To serve the nihari:
Put the nihari in a shallow serving bowl and garnish with chopped cilantro, chopped chillies and julienned ginger and sprinkle some fresh lemon in the gravy.