It is a layer of spices and vegetables that give biryani complex flavor and these spices can be used both as whole or as ground. In Biryani we also use herbs and seeds also that this is sometimes topped with fresh herbs, caramelized onions or dried fruits. So my my favourite food chicken biryani. There is Alumin spices and there are many types of biryani. Let me tell you some like Hyderabadi Biani