Rinse the basmati rice under cold water until the water runs clear, then soak for 20 minutes. Drain and set aside.
Marinate the chicken pieces with plain yogurt, cumin, coriander, turmeric, garam masala and chili powder. Let sit for 30 minutes.
Fry the sliced onions in ghee or oil until golden brown. Remove half for garnish. Add ginger and garlic to the pot and sauté briefly, then add the marinated chicken and brown on all sides.
Add chopped tomatoes and whole spices such as bay leaf, cloves and cinnamon. Cook until the tomatoes soften and the chicken is tender.
Stir in the drained rice and water or chicken broth. Add salt to taste. Bring to a boil, then reduce the heat and simmer until the liquid is mostly absorbed.
Cover the pot with a tight-fitting lid and cook on very low heat until the rice and chicken are fully cooked, about 15 minutes. Let the biryani rest off the heat for 10 minutes.
Fluff the biryani gently with a fork and garnish with the reserved fried onions and chopped cilantro and mint. Serve hot.