Wash all the lentils/dals and keep them soaked in water for 3 - 4 hours. Alternately, you can soak them in hot water for 30 t0 45 minutes. Clean and wash the meat and keep that aside.
In a pressure cooker, take all the dals and add water proportionately. Double the quantity of water. Add a little bit of salt and give it 2 whistles or let it cook for 15 minutes. Once done, let it slowly release the steam.
Finely slice the onions and deep fry them to a golden brown and keep them aside. If you don't want to deep fry, you can shallow fry also but it takes time that way.
In a heavy-bottomed pan or a kadai, take mustard oil and heat it. Add dried bay leaf and then the ginger and garlic paste and quickly stir fry it. Keep the heat at a medium or else it will burn.
Once the raw smell of the garlic goes away, add the fried onions (leave a little for garnish in the end). Immediately toss in the mutton pieces.
Over high heat, mix the onions with the mutton and brown the mutton pieces.
Whip the yogurt with turmeric powder, a little bit of salt, half a tsp of besan (which prevents the yogurt from splitting) and garam masala.
Add this whipped yogurt to the mutton and continue cooking it over medium to low flame. Once the spices have all assimilated, increase the heat and again stir fry for five minutes.
Then add 2 cups of water and pressure cook the mutton till it is tender.
Once the mutton is cooked, mix the mutton and the dal together in the saucepan (along with all the water from the dal boiling and the mutton boiling. Don't discard any liquid) and boil it.
Keep simmering till the dal has nicely cooked and has a semi-thick consistency with the tender mutton pieces.
Adjust salt, add crushed pepper and chopped green chilies.
Now in a tadka pan, heat ghee and add heeng and dried red chilies.
Pour this over the dal. Sprinkle chopped coriander leaves and fried onion.
Serve dal gosht with rice, roti or paratha.