Mix all the spices for the chicken with the yogurt, water, and olive oil. Combine with the rotisserie chicken pieces and allow to marinate while you prepare the rice.
Place the rice in a pot with 4 1/2 cups water, the salt, ground cloves, anise pod, ground cardamom, and bay leaves and bring to a simmer.
When a simmer is reached, turn the heat to medium low and cook the rice for 12 minutes (it should be just underdone). Remove the anise pod and bay leaves.
While the rice is cooking, fry the sliced onions in olive oil until just slightly charred and crisp, about 7 minutes.
Place the chicken, sauce and all, into a pot, and sprinkle half the fried onions on top. Cover and bring to a simmer.
Steep the saffron in 3 tbsp warm water, and melt the stick of butter.
Let the chicken simmer in the sauce for 5 minutes, then layer the rice over the chicken and press to cover.
Drizzle the saffron water over the rice, then drizzle the melted butter over the rice. Cover, and allow to simmer over medium heat for 10 minutes.
Scoop the biryani into bowls, being sure to include both rice and chicken in each scoop.
Serve topped with the rest of the fried onions, a spoonful of yogurt, and cilantro if you prefer.