Instructions
Fry the onions. Heat 2 tbsp oil in a wide heavy pan. Add sliced onions and fry on medium heat stirring often for 20–25 minutes until deep brown and crispy. Remove half and set aside for garnish. Keep the rest in the pan.
Marinate the chicken. In a bowl mix yoghurt, ginger-garlic paste, biryani masala, chilli powder, turmeric, coriander powder, and 1½ tsp salt. Add chicken and the fried onions from the pan. Mix thoroughly and marinate for 2 hours minimum.
Parboil the rice. Rinse basmati rice until the water runs clear; soak for 30 minutes. Bring a large pot of salted water to a vigorous boil with the whole spices. Add drained rice and cook for exactly 6 minutes — the rice should be 70% done. Drain immediately.
Layer the biryani. In a heavy pan spread the marinated chicken in an even layer. Layer the parboiled rice on top of the chicken. Drizzle the saffron milk evenly over the rice. Scatter mint, coriander, and 2 tbsp ghee on top.
Seal and dum cook. Cover the pot tightly — seal the edges with dough or foil if needed. Place over high heat for 5 minutes then reduce to the very lowest heat. Cook on dum for 25–30 minutes. The trapped steam finishes cooking the chicken and perfumes the rice.
Rest and serve. Turn off the heat and rest undisturbed for 10 minutes before opening. Gently mix from the bottom with a flat spatula without breaking the rice grains. Serve garnished with crispy fried onions and a wedge of lime alongside raita.