When you talk with anyone who has taken a holiday in Thailand, it takes no time at all for the conversation to turn to the great foods that are a "must try." For the adventurous traveler who wants more than just the beaches of the south or the Bangkok mega-city experience, the choice is Chiang Mai in the northern mountains and the "must try" food is Khao Soy.
Every region has local specialty dishes but when you say Khao Soy you are talking about Chiang Mai and the old Lanna Kingdom. It's not surprising that this noodle and curry soup dish may be the most delicious food of your stay in Thailand. What is surprising is that it will usually be the least expensive food on the menu.
I remember a travel writer describing the dish as Thailand's answer to fettuccine Alfredo but I think of it as the world's best chicken noodle soup. It's rich and creamy but not at all heavy, spicy but not hot. The soft texture of the flat egg noodles and stewed chicken is contrasted by the crispy fried noodles and crunchy vegetables garnishing the top. The pale orange/yellow color from the curry base is pleasing and the addition of some standard condiments can give a slightly sour or salty or acidic bite as preferred.
Khao soy was invented hundreds of years ago when Chiang Mai was a wealthy capital city and well placed to be a crossroads for trading. The noodles came with the traders' mule caravans from Yunnan, China in the north. Curry is believed to have come from India and across Burma to the west. Limes, shallots, lightly pickled cabbage, the richness of coconut milk and the talent for making deliciously balanced tastes were the local additions. The descendants of the Yunnanese traders still make some of the best Khao Soi in Chiang Mai ( especially on the small streets near the Ban Haw Mosque and across the Ping River next to Wat Faham) but it is also available in just about every other restaurant in the city with a Thai menu.
Like any food that's been around for centuries there are lots of variations in the preparation and closely guarded family recipes. Some can be complicated but the ones that always taste the best to me are the simple and quickly prepared home cooking style dishes. The ingredients are basic, it's the proportions that are the secret. In all of the methods, chicken cut into reasonable sized pieces is boiled in enough water to make a good stock. In a separate pot, fresh wide egg noodles are boiled for a very short time, drained and placed in a bowl. A thinner noodle has been fried crispy and set aside for garnish.
The soup begins with a prepared red curry paste that is heated in a pan until the paste begins to separate and become fragrant. As the pan heats, chopped garlic is thrown in and sauteed in the oil from the curry paste. When the garlic is cooked soft, coconut milk is added and stirred until the spices are fully dissolved. As the coconut milk becomes fully heated, pour in the stock from the boiled chicken to thin the soup to the desired consistency. At this point you can serve or hold everything at temperature until needed. When ready, pour enough of the hot soup to cover the noodles in a bowl and add pieces of chicken for a small serving. Garnish the top with the crispy noodles.
If you are faithful to the original, there are required condiments for individual use. Small wedges of fresh lime that can be squeezed into the soup are a must. Also standard are small amounts of coarsely chopped shallots and small pieces of cabbage that has been lightly pickled in sugar and salt. Although used very sparingly, Thais usually expect the table to have a bottle of fermented fish sauce, dark soy sauce and a chili sauce. Begin slowly and savor the richness, don't over use any of the sauces. They can add a little extra individual taste but they just aren't needed.
