Marinate the mutton: In a bowl, combine the yoghurt, mustard oil, star anise, ground cumin, coriander powder, red chilli powder, and salt. Add the fork-pricked mutton, rub the marinade in thoroughly, and refrigerate for at least 1-2 hours (or ideally overnight).

Parboil the rice: Rinse the basmati rice until the water runs clear. Parboil in lightly salted water until 70% cooked, then drain and spread on a plate to cool.

Prepare saffron milk: Dissolve the saffron in ¼ cup warm milk and set aside.

Fry the onions: Heat 2 tbsp ghee in a pan. Fry half the sliced onions until golden brown and reserve. Sauté the remaining onions with ginger and garlic pastes until translucent.

Cook the mutton: In a heavy-bottomed pot, heat the remaining ghee. Add cardamom, bay leaf, cinnamon, cumin seeds, and dried red chillies; let them crackle. Add the marinated mutton and sauté until the meat browns and the oil separates. Stir in the garam masala and cook until most of the liquid has evaporated. Remove the mutton to a plate.

Layer the biryani: In the same pot, spread half the parboiled rice. Top with all the mutton, dollops of cream, half the saffron milk, and half the reserved fried onions. Layer the remaining rice on top, then pour over the rest of the saffron milk and cream. Sprinkle mint, coriander leaves, and kasuri methi.

Dum cook: Seal the pot with a tight-fitting lid and cook on the lowest heat for 10-12 minutes, allowing the layers to steam together.

Serve: Remove the lid, gently fluff the rice with a fork to mix the layers, and transfer to a serving platter. Garnish with the remaining fried onions.