Lemongrass Sour Soup

This absolutely delicious soup has a deep rich flavor with lots of veggies, perfect on a cold or rainy day. The soup’s base is prahok and lemongrass (kroeung) with just the right amount of tamarind for natural sourness.

Samlor M'chu Kroeung Sach Ko – Beef and loads of water spinach in a sour and flavorful broth
Prep Time: 20 minutes
Cook Time: 45 minutes
Course: Soup
Cuisine: Cambodian
Keyword: Asian Soup, Cambodian Soup, Curry Leaves, Hot Basil, Khmer Soup, kroeung, lemongrass, Prahok, Sour Soup, tamarind, water Spinach
Servings: 10
Author: Channy Laux


  • 4.5 quart pot



  • Preparing the base – Cook prahok in oil over low heat until the moisture evaporates, add lemongrass paste, turmeric, Thnot sugar, and continue stirring until paste is firm and peels away from the pot.
  • Cook beef – Increase heat to medium-low, add meat, continue cooking until meat is completely seared, stir occasionally. Add 1 cup water and bring to boil, then cover and reduce heat; let simmer until the beef is tender about 30 minutes. Stir occasionally. You may need to add more water and simmer longer to get the meat done the way you like it.
  • Prepare water spinach – While the beef is cooking, trim and discard the old stems from water spinach. Remove most of the leaves, keep only a few at the very top. Wash and strain, then use a clever to smash the stems and cut into two inch lengths. Separate the stems and the tops of the water spinach; put cut stems into a large bowl of cold water. Set aside.
    Note – The cold water bath allows the water spinach to release its sap.
  • Add Thai Eggplant – Once the meat is done increase heat to high, add Thai eggplant, mix well. Continue cooking until the eggplant starts to welt.
  • Add water and tamarind – Add remaining water and bring to boil. Add tamarind.
    Note – It is important to add tamarind prior to adding the water spinach, which allows the vegetables to stay crunchy.
  • Add vegetable – Add water spinach stems and stir, turn off the heat and add the water spinach tops, chiles, and hot basil. Salt to taste. Do not cover the pot.
    Note – Covering the pot while it's still hot will cause the green vegetables to turn brown.


Best served with steam rice and fish sauce with birds eye chili. 
*Variations and Substitutions:
  • Prahok is Cambodian fermented fish paste. The best substitute for prahok is fish sauce or anchovy paste.  
  • Variations of different protein used for this soup include: fatty beef trimmings, cow stomach and tripe, pork spare ribs, and freshwater fish or shrimp.  My favorite is with fish, specifically grilled fish that has been deboned and then added to the soup while the broth is boiling. 
  • Ripe and concentrated tamarind paste adds sour and a fruity notes to the soup.  In Cambodia, acidity for the soup comes from many source including: young tamarind leaves, tamarind flowers, green tamarind fruit, ambarella (kuntout) leaves , feroniella lucida (krawsankg) fruit, schleichera (pongro) berries, and even green mangoEach of these sour leaves, flowers, fruit and berries brings out their own unique flavor in the soup.  The decision of which sour ingredient to use most often depends on seasonal availability. Many times the soup is made just for the taste of certain kind of sourness before its season is over.  Since ripe tamarind can be preserved year round, it is the most common recipe for the soup, especially when cooking with beef.  
  • Water spinach is wild, abundant and available year round in Cambodia. During the monsoon season, water spinach is most tender and luscious, it grows mostly under flood water in the rice fields or near a lake.  During the dry season it grows like ground cover with short and tender tops packed with sap and strong flavor.  Thus, during the dry season most people would rather make the soup with other vegetables such as kai choy, or mustard greens.  You can also add other variety of vegetable into the soup along with the water spinach.  They include pearl eggplants, Thai eggplants, jalapenos, and celery.  If you have to use vegetables other than water spinach, reduce the prahok to one tablespoon.  For some reason water spinach sucks up the prahok flavor, leaving the soup less bold.  
  • Hot basil (M’reas prouv) has similar aroma as oregano but not as strong, thus to substitute hot basil with oregano use about 1/4 to the quantity calls out in the recipe.  A variation to the soup is to use curry leaves (Sloek kontroap), by roasting them over a hot charcoal if you happen to have BBQ while cooking the soup.  For convenience, roast the leaves in oven at 375ºF for 10 minutes.  Use your hands to crumble the leaves while adding to the soup.    
Angkor Lemongrass Paste (Kroeung)
Angkor Tamarind Concentrate
Tried this recipe?Mention @AngkorFood or tag #angkorfood, thank you!

Published by Channy Laux

Channy Laux is a survivor of the Khmer Rouge genocide in Cambodia. She was thirteen-years-old when the Khmer Rouge took over the country in 1975. From 1975 to 1979, Channy endured starvation, horrendous working conditions, sickness and repeated separations from her family. In June of 1979, Channy arrived in Lincoln Nebraska as a refugee. After four years of no school and not knowing a word of English, she attended Lincoln High School; earned a Master of Science in Applied Mathematics from Santa Clara University and undergraduate degrees from the University of Nebraska-Lincoln. Channy worked in Silicon Valley as an engineer in the Aerospace and Biotech industries for 30 years. In 2017 Channy decided to focus on completing a promise that she made to herself as she and her family struggled to survive the Cambodian genocide. “If I ever make it out alive, I will make sure the world knows what happened to us.” Channy published her memoir “Short Hair Detention”, which receives multiple awards, including Nebraska’s 2018 Book Award. Channy is also founder of Angkor Cambodian Food. Her goal is to bring Cambodian cuisine into American kitchens, by providing authentic and hard to find ingredients along with easy to follow recipes. One of her creations Kroeurng (Lemongrass cooking paste) receives sofiTM Award from Specialty Foods and Innovation Foodservice Award from IFMA. Channy now balances her time between her business and educating communities on the Cambodian Genocide. She works with schools and other organizations to promote awareness of Cambodian Genocide. She is a member of Speakers Bureau for JFCS Holocaust Center.

2 thoughts on “Lemongrass Sour Soup

Leave a Reply