Made from rice flour and water, these are the most common noodles in Vietnamese cooking. When thin, long, and round, they’re called rice vermicelli (bun). (Bun is also the name of herb noodle salad, always made from rice vermicelli.) Banh hoi is the thinnest version, resembling fine hair, and is most commonly steamed into banh hoi squares. Two thick rice noodles are bun rieu and bun day. Thin, flat, and wide rice noodles are known as rice sticks, or pho and hu tieu noodles. Though banh pho and banh hu tieu are similar in texture, hu tieu have some tapioca flours that make them a bit tougher than pho noodles. Depending on their thickness, rice noodles are either soaked in hot water or boiled for a minute or two to cook. Transparent when cooked.