Marination:
Marinate Mutton using hung curd, 1 tsp red chili powder, 1/2 tsp turmeric powder, lemon juice, 1 tsp salt, 1/2 cup chopped mint leaves. Allow the mutton to marinate for at least 1 hours.

Preparation:

Now Slice 3 onions very thinly. Separate the slices.

In a pan or kadai add oil and fry the onion slices till nicely brown.(Take care not to burn them)
Take the fried onions out with a slotted spoon or ladle.Keep them on a paper-towel lined plate.

In the same pan fry potato wedges till crispy.

Fry the Cashews till slightly brown.

Take 1/3 of fried onions and to the marinated mutton.
Cooking Mutton:

Take ghee in a pan or cooker.

Add all the whole spices (cinnamon,cloves,pepper,cardamon, bay leaf, cloves and dried red chili).

Once the spices give out aroma add ginger and garlic paste.

When the ginger and garlic paste cooks add 1 sliced onion and cook till it gets soft ( add a pinch of salt to speed up the process)

In a small bowl mix all the spice powder that is red chili, turmeric,coriander, garam masala ,biryani masala and 2 tbsp water.

Add the spice mix to the onions and cook for 5 min.

Now add mutton and keep cooking till the oil separates.

Once the oil separates add enough water to cook the mutton (around 1 cup or more) and close the lid.

Cook till mutton is soft and cooked. (at least 20-30 min)

Add kasuri methi at the end.

Check the seasoning add salt if needed.
Cooking Rice:

Boil large pot of water for the rice. (you can add salt, 1/2 tsp vinegar, lemon , and whole spices like bay leaf ,cloves etc to give rice some extra flavor)

Cook the rice till its 75% done and drain out the water.

Take 1/4 cup luke warm milk and add few saffron strings to it and mix well.

Now take half of the rice in a different bowl and add the saffron mixture and mix gently so that all the rice grains are yellow.

Take 1/4 cup of rose water and add it to the remaining white rice.
Assembling Biryani:

In a large pot or pan in which you are going to serve the biryani make the bottom layer with mutton.

Make a layer with half of the rice on top of the mutton.

Put half of chopped mint, coriander, fried potato, cashews and onions.

Put remaining rice and again top it with remaining mint,coriander,potato,cashews and onions.

Take a foil and make a small bowl shape out of it and place in the center of your biryani. Take a chunk of coal and heat it up on you gas flame. Once it gets hot place it in the foil and put 1 tsp of ghee on the hot coal. (coal will give out smoke)

Put the lid and cook for 10 min.

Serve the Biryani with raita.