Khao soi or khao soy (Thai: ข้าวซอย ; Lao: ເຂົ້າຊອຍ ) is a Burmese-influenced dish (see on no khauk swe) served widely in northern Laos and northern Thailand. The name means "cut rice". Traditionally, the dough for the rice noodles is spread out on a cloth stretched over boiling water. After steaming the large sheet noodle is then rolled and cut with scissors. Lao khao soi is still made with the traditional noodles and in some markets in Luang Namtha and Muang Sing you can still see the vendors cutting the noodles.
There are two common versions of khao soi:
- Lao khao soi is a soup made with wide rice noodles, coarsely chopped pork, tomatoes, fermented soy beans, chillies, shallots, and garlic, then topped with pork rind, bean sprouts, chopped scallions, and chopped cilantro. Though northern Laotians have a special way of preparing this dish, different versions of it can be found at Lao restaurants.
- Northern Thai khao soi is closer to the present day Burmese on ne khauk swe, being a soup-like dish made with a mix of deep-fried crispy egg noodles and boiled egg noodles, pickled cabbage, shallots, lime, ground chillies fried in oil, and meat in a curry-like sauce containing coconut milk. The curry is somewhat similar to that of yellow or massaman curry but of a thinner consistency. It is popular as a street dish eaten by Thai people in northern Thailand, though not frequently served in Thai restaurants abroad.
There is some reason to believe that the Thai version of khao soi was influenced by Chinese Muslim cuisine and was therefore likely served with chicken or beef.
Khao soi is featured in the cuisine of the Shan people who primarily live in Burma. This version of khao soi, as well as the version in Chiang Rai Province, can contain pieces of curdled blood.