If you're an incessant snacker, as I am, you'll find Vietnam paradise. You don't need to walk far to find something small to nibble on. Street vendors serve their wares in small portions, so even a bowl of pho can be eaten as a snack, and it won't ruin your appetite for a main meal later on.
One soupy snack that deserves to be better known is bun bo Hue. As you can tell from its name, the dish originated in Hue, in central Vietnam. It's a pungent bowl: the beef broth is flavoured with fermented shrimp paste and chilli, before being ladled over rice noodles. The first time I ate it, the vendor looked at me questioningly before adding the supplementary ingredients: she was unsure if I'd eat pig's feet (yes!) and pig's blood (yes!). When I went back for a bowl the next day, she didn't bother asking: she just added the ingredients to the bowl.
As with most other dishes in Vietnam, bun bo Hue is served with a pile of greens, which you can use to customise your bowl: lime wedges, bean sprouts and herbs such as culantro, basil and fresh coriander.