Order it with the works: pork, pâté, pickled daikon-carrot, cucumber, cilantro, chili, and a splash of soy or Maggi.
Bánh Mì 25 (Hà Nội) and Bánh Mì Huỳnh Hoa (HCMC) are pilgrimage-worthy. Both have lines — they're worth it.
Veg options exist (mushroom pâté, fried tofu). Ask for 'không cay' if you don't want chili.