Biryani is a layered rice-and-meat dish built by par-cooking spiced chicken and partially-cooked rice separately, then steaming them together so the rice finishes cooking in the chicken's fragrant juices. Whole spices -- cardamom, cinnamon, saffron -- perfume the rice without overwhelming it, while deeply caramelized onions tie the layers together. Getting the layering and final steam right matters more than any single ingredient -- it's what separates a true biryani from simply spiced rice with chicken stirred in.