The broth for beef phở is generally made by simmering beef bones, oxtails, flank steak, charred onion, charred ginger and spices. Seasonings can include Saigon cinnamon or other kinds of cinnamon as alternatives (may use stick or powder), star anise, roasted ginger, roasted onion, black cardamom, coriander seed, fennel seed, and clove. The broth takes several hours to make. For chicken phở, only the meat and bones of the chicken are used in place of beef and beef bone. The remaining spices remain the same, but the charred ginger can be omitted, since its function in beef phở is to get rid of the "cow's smell"