Banh Mi Thit (meat) or Chay (vegetarian)
This is a warm and crunchy baguette that is filled with many different combinations. It could be several kinds of Vietnamese pork ham, liver paste (pâté gan), veggies (cucumber, coriander, green onion, chili...) and sour things (đồ chua) which are made from pickled shreds of carrot and white radish. There are many vendors selling these and you can get them made to your taste.
The vendors are everywhere. Some are only open for breakfast, some lunch and some dinner and late night.
These are eaten for breakfast, lunch, dinner and a snack. They are very cheap and filling. Expect to pay around 10 000 - 20 000VND each.
A favorite for breakfast is Banh Mi opla (fried egg in a bread roll), sensational!