In a large dutch oven, add the ingredients to the marinade; chicken thigh pieces, yogurt, oil, ginger & garlic paste, red chili powder, garam masala, salt, turmeric powder, mint, and cilantro. Mix until well combined. Allow the chicken to marinade for at least 30 minutes.
Meanwhile, prepare the brown onions. Heat a skillet with oil on medium heat. Once the oil is heated, add the sliced onions and saute for 7-10 minutes until the onions are browned. Set it aside.
In a small bowl, soak the saffron in warm milk and set it aside.
Start cooking the marinated chicken in the same dutch oven for 7-10 minutes.
Meanwhile, start cooking the rice; boil the salted water along with the cloves, cardamom, bay leaf, and star anise. Add the basmati rice and cook until the rice is 70% cooked. Once done, drain the water.
Start layering for biryani; Add a layer of browned onions over the cooked chicken, followed by chopped mint and cilantro. Spread the cooked rice in an even layer.
Add the ghee and saffron milk on top of the rice. Close the dutch oven with a lid and cook on low heat for 15-10 minutes.
Once done, allow the biryani to rest for 10 minutes. Serve the chicken biryani with raita on the side to enjoy.