Heat oil in a pan. Add the chopped onions and stir them on medium heat. Reduce the heat after the onions have begun to change color. Remove them from the pan when they are golden brown and place them on a plate.
Let the oil and fried onions cool down.
In the meantime, in another pan (turn off the heat) add 2kg beef. Beef needs to be cut into regular size pieces, washed, and drained before adding.
Add chopped onion, garlic, and ginger. They needed to be chopped into little bit bigger sizes than usual.
Add shahi cumin, dried chilies (cut into pieces), black pepper, cardamom, cinnamon, bay leaves, cloves, salt.
Add the cooled oil and salt.
Mix them all. During mixing add the fried onions and mix very well.
Turn on the heat. Close the lead and cook for 10 minutes.
Add the sour yogurt. Beat the yogurt well before adding.
Cook for another 60 minutes. Stir occasionally.
Remove the lead and cook until water is reduced.
Add 2 cups of water.
Cook for another 40 minutes. Stir occasionally.
Leave the broth as desired. Your delicious "Kata Moshlar Gorur Mangsho" is ready.
Serve with rice, pulao, or porata.