Marinate the chicken: In a large bowl, combine the chicken, yogurt, lemon juice, ginger garlic paste, green chili, oil, salt, turmeric powder, red chili powder, garam masala, coriander powder, roasted cumin powder, mint leaves, and coriander leaves. Mix well and marinate for at least 30 minutes, or overnight in the refrigerator.
Cook the rice: Bring a large pot of water to a boil. Add the rice and cook until it is 70% done, about 10 minutes. Drain the rice and set aside.
Cook the chicken: Heat the ghee or oil in a large pot over medium heat. Add the onions and cook until they are softened and translucent, about 5 minutes. Add the marinated chicken and cook until it is browned on all sides.
Add the rice and spices: Add the rice, salt, garam masala, and coriander powder to the pot. Mix well and spread the rice in an even layer.
Add the saffron milk: If using, pour the saffron milk over the rice.
Seal the pot and cook on low heat for 15 minutes, or until the rice is cooked through.
Garnish and serve: Garnish the biryani with fried onions and coriander leaves. Serve hot with your favorite accompaniments.