Cao lầu is a Vietnamese noodle dish from Hội An known for thick noodles, pork, herbs, and very little broth.
Its noodles are traditionally associated with Hội An and are characteristically thicker and chewier than ordinary rice vermicelli. The dish is commonly assembled with slices of roast pork, fresh herbs, bean sprouts, greens, and crisp pieces of fried noodle dough.
Cao lầu is often described as a regional specialty rather than a general Vietnamese noodle soup. Its preparation has also inspired stories about local well water and wood ash, although modern production methods vary.
A common mix-up is calling cao lầu a soup. Unlike phở or bún bò Huế, it contains only a small amount of concentrated liquid, so the noodles and toppings remain the focus.