Combine yogurt, ginger, garlic, turmeric, red chili powder, biryani masala, salt, mint leaves, and lemon juice in a large bowl. Add chicken and coat evenly. Refrigerate for at least 30 minutes, or up to 24 hours for deeper flavor.
Heat ghee in a pan over medium heat. Fry onions until they are golden brown, taking about 15-20 minutes. Remove and set aside.
Boil water with cumin seeds, bay leaves, star anise, cardamom, cloves, and salt. Add soaked and drained rice, cooking until it's 90% done, then drain well.
In the same pan with residual ghee, add marinated chicken. Cook for 8-10 minutes, turning midway for even cooking.
Layer the partially cooked rice over the chicken, topping with crispy onions and saffron-infused milk. Cover tightly and cook on low heat for 20 minutes. Allow to sit for 10 minutes before gently fluffing with a fork.
Serve piping hot with cool raita and lemon wedges for a balanced meal.