Peel potatoes and smear on them yellow food colour. Keep the potatoes whole. Heat vegetable oil, 3 cm deep, in a pan. Fry the potatoes until they are lightly coloured on all sides (about 4 minutes). Drain them from the oil and set aside.

In a pan set over medium heat, add all the spices in the given proportions for ‘biryani masala’ (see section). Gently toast them, stirring continuously. Transfer the toasted spices to a spice grinder and grind them to a fine powder. Weigh two separate portions of biryani masala.

Peel ginger and garlic, roughly chop them, and make a fine paste. In a large mixing bowl or pressure cooker, mix together yoghurt, ginger and garlic paste, birista, kewra water, biryani masala, red chilli powder, salt, and ground pepper, in the proportions given above for ‘marinating mutton’. Add the mutton pieces and coat them well with the marinade and cover and set aside for 1 hour.

Meanwhile, wash the rice and soak it in water for 30 minutes. At the end of this time, drain the water and strain the rice over a net or colander. Set aside. Soaking leads to longer and fluffier rice grains.

After the mutton has had 1 hour to marinate, transfer it to a pressure cooker. Lay the fried potatoes at the bottom of the pressure cooker, followed by the mutton on top.Add 150 g water and pressure cook it on medium-low heat for 30 minutes. Allow the steam to release naturally for another 15 minutes before opening the lid of the pressure cooker.

Separating mutton, potatoes, and yakhni: Extract the potatoes and mutton pieces in separate dishes and set them aside. Now strain the liquid remaining in the pressure cooker. This is called ‘yakhni’ (a broth resulting from mutton and spices cooked together).

Place the spices mentioned in the ‘rice’ section above in the given proportions on a small square of cheesecloth and tie to form a potli.In a large pot, take 3 kg water. Add 1 tbsp salt to it. Add the bag of spices to the water and allow it to come to a boil.

Set the biryani handi or pan you are using for dum on low heat. Grease it with ghee. Lay bay leaves in a single layer to cover the bottom of the pan. These will impart an aroma and provide buffer against burning. Place the mutton pieces in a single layer, and the potatoes on top of the mutton. Don’t place potatoes too close to the edge or you might accidentally cut into them while serving. Sprinkle the birista.

Take half the stipulated amount of biryani masala and khoya kheer, and spread evenly. We will use the remaining half in the next layer.Now add the yakhni and lime juice.By this time the water for rice should have come to a boil and its colour changed. Extract the bag of spices and discard it. Add the rice and let it cook until 80% done, that is, until when the centre is no longer hard, but the grain is still firm.

Strain rice, a ladle at a time, and spread it directly in the pan. Repeat this until half the rice is added to the pan.On top of this first layer of rice, spread the remaining biryani masala and khoya kheer. Also spread the saffron+colour mixture evenly.Now strain the rest of the rice and add it to the pan. Flatten it gently.

On top of the second layer of rice, add milk mixed with the aromatics. Also add ghee, making sure to drizzle it near the sides of the pan. Add the boiled eggs in between the rice.