What is the name of the Lao-Thai rice noodle soup from Isan?

The Lao-Thai rice noodle soup from Isan is khao piak sen. Its name refers to “wet rice strands,” describing the fresh noodles cooked directly in the broth.

Khao piak sen is traditionally associated with Lao cuisine and is also eaten in northeastern Thailand, where Lao culinary traditions strongly influence Isan food. The soup commonly uses chicken, pork, or both, with aromatics such as galangal, lemongrass, kaffir lime leaves, and garlic.

Its noodles are distinctive: rice flour is combined with tapioca starch to create thick, chewy strands somewhat reminiscent of udon. Cooking them in the soup releases starch, giving the broth a lightly thickened texture. Bowls are often finished with shredded meat, herbs, fried garlic, chili, lime, and fish sauce.

It is easy to confuse khao piak sen with khao soi, another Southeast Asian noodle soup. Thai khao soi is usually a curry-based dish with egg noodles and crispy noodles, while khao piak sen is a clear Lao-style soup with fresh, chewy rice-and-tapioca noodles.