Grind black peppercorns, cloves, cardamom, cinnamon, star anise, and cumin seeds into a fine powder. Finely chop mint and coriander leaves. Add dry spice mix, chopped mint and coriander leaves, and other marinade ingredients in a mixing bowl and combine all of them. Add the chicken and coat it well. Use plastic wrap to cover the bowl and let the marinated chicken sit in the refrigerator for about 2 hours. Wash the rice thoroughly. Take a saucepan and add water and rice in it. Once it boils, add 2 bay leaves and reduce the heat to medium-low. Cover and let it simmer until rice is partially cooked and is firm. This might take about 5 minutes. Once done, drain the rice. Add saffron to a bowl of milk, stir and keep it aside. Add ghee to a large pot with a tight-fitting lid or a pressure cooker, heat it over medium-high flame. Stir in onions until golden brown for about 15 minutes. Drain them on a paper towel. Switch the flame to low and add bay leaves, chillies, and stir for about 1-2 minutes. Remove a tbsp of ghee from the pot and set it aside. Add the chicken along with the marinade into the pot and cook for 2 minutes per side until it’s no longer pink. Spread the drained rice on top, sprinkle fried onions and drizzle ghee with saffron milk on top. Cook for 8-10 minutes over a high flame covered with a lid. Then reduce the flame to low and continue cooking for 5 minutes. Turn off the flame and let it stand covered for about 15 minutes. Garnish with mint and coriander leaves on top. Serve hot with raita or green salad.