Whisk ⅔ cup of plain yogurt with 1¼ tablespoons of ginger-garlic paste, 1 tablespoon of lemon juice, 1 teaspoon of red chili powder, 1 teaspoon of biryani masala, ¼ teaspoon of ground cardamom, and ¼ teaspoon of turmeric.
Mix in 500g of skinless, bone-in chicken thighs and drumsticks, 1 slit green chili, and ¾ teaspoon of salt. Cover and marinate while you prepare the rice and onion. Rinse 1½ cups of aged basmati rice and soak it in water.
Heat 4 tablespoons of oil in a large heavy pot and fry 1 large thinly sliced onion until golden brown. Lift out the onion, leaving the oil in the pot.
Boil 7 cups of water with 1 bay leaf, 1 cinnamon piece, 3in / 7.5cm long, 6 whole cloves, 4 green cardamom pods, 1 star anise pod, 1 teaspoon of salt, and 1 teaspoon of oil. Par-cook the drained rice in it until still firm, then drain.
Spread the chicken and its marinade in the pot. Mix 4 tablespoons of chopped mint and 4 tablespoons of chopped cilantro; scatter half the herbs and half the onion over the chicken. Cover with the rice, then the remaining herbs and onion.
Pour over 1 large pinch of saffron soaked in 3 tablespoons of hot milk and drizzle with 2 tablespoons of melted ghee. Seal the pot with foil and a heavy lid.
Set the pot on a hot griddle over medium-high heat for 20 minutes, then over the lowest heat for 15 minutes. Rest off the heat, unopened, for 20 minutes. Check that the chicken has reached 165°F / 74°C.
