Cambodian Hot and Sour Coconut Soup with Catfish (Somlar Machu Ktiss)

Cambodian Hot and Sour Coconut Soup with Catfish (Somlar Machu Ktiss)

Cambodian Hot and Sour Coconut Soup: Healthy and Wholesome

Somlar Machu Ktiss (Cambodian Hot and Sour Coconut Soup) is almost as complex as Cambodian curry, so it doesn’t make regular weekly appearances on our dinner plate, but when it does, I always jump in joy and anticipation. So healthy, explosively flavourful, complex and beguilingly delicious, I can’t help but go for a second or a third round. Needless to say, there are never any leftovers when my mother prepares this somlar machu ktiss. 

Over the years, I’ve come to realize that I am quite lucky. While my friends struggle with the newest diet fads, juice cleanses or paleo diet, I am regularly spending my time as usual; visiting the local farmer’s market for fresh ingredients. Cambodian diet is full of vegetables, fermented foods and a minimal amount of lean proteins, so I have always been lean and healthy. My mother prepared wholesome meals from scratch so artificial ingredients and processed foods were a rarity in our household. Even now, in my own household, processed or artificial food is not something I approve of, although somehow it does manage to sneak in from time to time (thank you, Jose, you sneaky devil!).

Although Cambodian food is very healthy, to get that complex taste and vibrant colour, fresh ingredients are pounded to a pulp with a mortar and pestle to make the spice (kroeung). Preparing it fresh can be daunting for first-timers, especially when looking at the ingredient list. Hopefully, for the many curious foodies, this wouldn’t be a hard obstacle to overcome as the ingredients can be easily found at an Asian supermarket.

Finding Ingredients for Cambodian Hot and Sour Coconut Soup with Catfish

The most difficult ingredient to find is Galangal, a rhizome, used heavily in Indonesian, Thai and Cambodian cuisine. Galangal may look like an upscale version of ginger at first glance and one may assume it is just another variety of ginger, but they are actually quite different. Ginger has a sharp pungent taste whereas galangal’s pungency is more muted and packed with a more medicinal, piney notes. The skin of galangal is tighter and much lighter in colour, almost translucent, and its flesh is quite dense –almost as hard as wood. For this recipe, galangal cannot be replaced with ginger —it is acting as a freshener to cut out the fishy taste of the catfish. 

Similar to ginger, galangal has numerous medicinal uses and health benefits. Like turmeric, it has many anti-inflammatory qualities and is therefore very helpful in treating arthritis,  rheumatoid arthritis, as well as inflammation caused by ulcers. Feeling a little nausea? Chew on a little hunk of galangal to help ease symptoms of motion and morning sickness. Galangal also improves circulation, maintain healthy digestion, and helps alleviate diarrhoea.

Galangal is available fresh at most Asian supermarkets but you can also find it preserved in brine which is also just as good as fresh, although with a much longer shelve life (and much easier to cut!). If you are using whole fresh galangal, you might find that your knife will literally just slide over it if it’s not sharp enough, in which case, just soak it in hot water before attempting to slice it again.

kroeung to make somlar machu ktiss or cambodian hot and sour coconut soup

There seems to be a turmeric fad lately, so this is an ingredient that shouldn’t be hard to find. If it is hard to find fresh turmeric, turmeric powder can be used instead. There’s no preference really, it’s just there for colouring and health purposes. It doesn’t affect the flavour as much as galangal, whose fresh whole form (or brined form) is a necessity to cut the fishy taste of the catfish which will be used for this recipe.

kroeung pounded in a mortar and pestle to make somlar machu ktiss or cambodian hot and sour coconut soup
Tip for convenience: Place all the kroeung ingredients into a grinder and grind it to a coarse paste, then move it over to a mortar and pestle to finish the work. Pounding the kroeung in a mortar and pestle allows the flavours to assimilate and harmonize to give your soup that balance but complex flavours. If your kroeung looks like this picture, it’s not ready, pound it until it looks like store bought curry paste.

For this Cambodian Hot and Sour Coconut soup recipe, we will be using Thai eggplants, long beans and catfish. Thai eggplant is a very common food ingredient in Cambodia. Usually the size of a golf ball or smaller, mostly round, they range in colour from all green to green with stripes and a few streaks of purple or yellow. Unlike the larger oblong eggplants, Thai eggplants are crunchy but tender on the outside, with a mild flavour and a tiny hint of delicate bitterness on the inside. Which is why they are mostly enjoyed raw (and unskinned) in the Cambodian household, usually served with a dipping sauce made from fish such as tirk kroeung or prahok ktiss which is a dipping sauce made from pork and coconut milk. 

When eaten raw, Thai eggplants are better in its immature state, so look for smaller/younger ones that are glossy and colourful. When eaten raw, their scent is also very mild and neutral, however, when cooked, they develop an earthy aromatic scent. When overly mature, the flesh is more bitter and stringy, especially their seeds. Yes, they have seed. And due to this, they are actually classified as fruits even though many consider them as a vegetable (me included).

Mainstream supermarkets or farmer’s market don’t usually have them so the best way to get Thai eggplants would be in an Asian grocery store. If you’re able to buy them individually, make sure to look for the freshest ones —the stem should be green rather than brown and firmly attached to the eggplants. They should be firm with dark green tones, avoid ones that have too many streaks of yellow.

thai eggplant and long beans for somlar mach ktiss or cambodian hot and sour coconut soup

I usually do not like catfish, but in this somlar, the delicately mild flavour of catfish whose taste is almost similar to that of a sweet whitefish works well to balance the heat and flavours of the soup. One great thing I like about catfish is that it is naturally low in sodium which is great for those on a low-salt diet or those that trying to reduce or avoid high blood pressure. Although I do love my salmon, adding catfish to my diet not only adds variety to my meal. it also a great low-fat and healthy alternative.

How to clean catfish for Cambodian Hot and Sour Coconut Soup

Place the whole catfish (innards removed) into a bowl. Add 2 tablespoon of vinegar and 1 tablespoon salt into the bowl and fill it with water. Scrap the skin of the catfish to remove any dirt and slime while in this solution. Once clean, remove from the solution, wash it with water and cut it into chunks (see picture below).

catfish cut into chunks for cambodian hot and sour coconut soup

This Cambodian Hot and Sour Coconut Fish Soup is one of those healthy, hearty meal that everyone in the family will love. My recipe is a bit on the spicy side, but you can turn down the heat if you prefer, but personally, I love the spiciness. It keeps me warm during those cold winter months and cools me down in the summer (from all that sweat!). Either way, give this somlar machu ktiss a try today!

somlar machu ktiss or cambodian hot and sour coconut soup with catfish

Want more Cambodian food recipes? Try these out!

Cambodian Sour Soup: Somlar Machu Kroeung
Cambodian Sour and Spicy Steamed Fish with Lemongrass and Galangal
Cambodian Stuffed Chicken Wings
Cambodian Noodle: Num Banh Chok
Ginger Fish with Salted Soybean: Trey Chean Choun

4.91 from 11 votes
somlar machu ktiss or cambodian hot and sour coconut soup with catfish
Cambodian Hot and Sour Coconut Fish Soup with Thai Eggplant and Long Beans (Somlar Machu Ktiss)
Prep Time
20 mins
Cook Time
20 mins
Total Time
40 mins

Cambodian hot and sour coconut soup with catfish is a complex Cambodian soup with a bold but balanced flavour of spiciness, sour and savoury. Made with Cambodian kroeung of lemongrass, galangal, kaffir lime leaves simmered in coconut milk, this is a very healthy, paleo dinner usually made with all fresh ingredients.

Course: Main Course
Cuisine: Cambodian
Keyword: Cambodian hot and sour coconut soup with catfish, Cambodian soup, Cambodian soup recipes, Hot and sour soup recipe
Servings: 4 people
Author: Yuen Mi | A Wandering Foodie
Kroeung for Somlar Machu Ktiss
  • 11 kaffir lime leaves
  • 1/2 cup lemongrass (2 stalks)
  • 3/8 cup galangal (1 root, length of thumb)
  • 1 teaspoon turmeric powder
  • 4 bird's eye chilli peppers
  • 2 tablespoon roasted red pepper paste or thai red curry paste [ see note ]
  • 1 tablespoon shrimp paste [ kapee/kapi ]
  • 1 tablespoon tamarind powder (knorr)
  • 2 catfish [ cleaned, see above for how to clean ]
  • 10 Thai eggplants
  • 1 bunch long beans
  • 1 tablespoon peanut oil
  • 2 cups coconut milk
  • 1/2 teaspoon salt
  • 1 tablespoon fish sauce
  • 2 cups water or chicken stock
  • cane sugar to taste
  1. Cut lemongrass, galangal and half of the kaffir lime leaves into tiny thin slices. Place them in a mortar and pestle along with turmeric powder, Thai bird's eye red chilli peppers, shrimp paste and red pepper paste (or red curry paste). Pound into a fine paste to make kroeung.

  2. Add oil to a pot or deep frying pan. Once heated, add kroeung and stir so the kroeung doesn't burn. 

  3. Once fragrant (about 2 - 3 minutes), add catfish and toss to mix the ingredients. 

  4. Add coconut milk, tamarind powder, salt and fish sauce.  Rip up the other half of the kaffir lime leaves and add it to the pot. 

  5. Add the long beans and let it come to a boil. Turn down the heat and let it simmer for 5 minutes before adding the Thai eggplant.  Let it simmer for 10 minutes or until the coconut soup thickens a bit. Add 2 cups of water. Add extra fish sauce or cane sugar to your taste.

Recipe Notes

Roasted Red Peppers

Both in my Cambodian curry recipe and this one, I just used Thai Red curry as a replacement, but to do it properly, with the most authentic taste, you should use roasted red peppers. 

Wash the red peppers and dry them. Grill/oven them on the lowest heat possible and let it cook for 2 - 3 hours until they are cooked, and dried. Once dried, they can be kept whole for a very long time, no need for refrigeration. To use for this recipe, soak the dried red peppers in water for a bit before transferring it into a mortar and pestle. You want to pound the peppers into a fine paste.

Or, you could purchase dried red peppers at any supermarket, soak the amount you need in water, transfer it to a mortar and pestle, and pound it into a fine paste. 

Love this post? Pin me for later!

cambodian hot and sour coconut soup with catfish somlar machu ktiss


Enter you email below, and click subscribe to sign up for my monthly newsletter!

1. Be the first to get notified on new updates
2. Get free cambodian food recipes straight to your inbox
3. You won't regret it =)

I am based in Canada, but, because EU god wants me to be GDPR compliant, I need to give this warning before you sign up for our email newsletter. Even though I know you probably already know what you're signing up for: This double opt-in form collects your email so that we can add you to our newsletter list for awesome post updates. For more information, check out our privacy policy.
* indicates required

Related Post


  1. Love to eat some spicy soup ! !

  2. Amazing things here. I’m very glad to see your post. Thank you a lot and I am having a look ahead to contact you. Do taste the food in andaman Nicobar It’s So Emmy and tasty.

  3. I am hosting a party based around Cambodian food. I am not a big catfish fan and m wondering if there’s an alternative fish you could recommend. Also wondering if you would put this on top of a little rice? Thanks. Recipe looks delicious. Can’t wait to try it.

    1. You can use any fish you want really. I haven’t tried it with salmon, but I think salmon would work great with it since It tastes good in somlar machu. We usually eat this dish with rice on the side, or on top of rice. Either way, it’s great. Have a great party!

  4. Holy moly this sure looks unique and delicious!

  5. wow very informative post i really like this post and love to eat fish thanks for providing this great recipe and very nutritious thanks

  6. I love catfish, such an exotic fish which I enjoy cooking with abundant coconut milk, ginger, and garlic.

  7. Amazing things here. I'm very glad to see your post. Thank you a lot and I am having a look ahead to contact you. Will you please drop me a mail?

  8. you take some gorgeous photographs! i too am not a catfish fan but great photos!

    Joy at <a href=“”>The Joyous Living</a>

  9. I’m not much of a cook but this dish looks absolutely delicious. I might have to pass this on to my husband who is the cook in our house 🙂
    Thank you for sharing 🙂

    1. Thank you! I hope you enjoy it when your husband gets the chance to try it out. And any feedback would be greatly appreciated! 🙂

  10. I'm not a big fan of catfish, but my grandmom is. I bet she will love this dish. 🙂

  11. Yum! This sounds so good! I've never had Cambodian soup but it sounds delicious! And your pictures are gorgeous!

  12. This is so different than what I would normally try but it does look really good!!

  13. I haven’t tasted this soup or it’s ingredients together before, but I’m all over this recipe. I could eat soup everyday and will definitely give this one a try. Looks amazing!

  14. Oh, this so yummy, I just love South East Asian recipes like this one. Having grown up in that region, I could eat this every day! I smiled when I read your description of galangal. I've been teaching South East Asian cooking for about 20 years, and am always bemused when I see people subbing ginger for galangal! Fabulous recipe!

  15. I love hot and sour soup and the flavors in this one are on point. I'm definitely going to be making this for my family when they come in town.

  16. Oh wow! This is a very impressive looking soup. My son and husband often go fishing in our creek and come home with huge catfish. I'll have to share this recipe with them.

  17. This looks and sounds amazing! I've never tried Cambodian food, but I love Thai and Indian and it sounds a little similar to both. Here in Italy it's difficult to find all the ingredients but I'd love to make this! Those eggplants are so cute!!

  18. Such a flavorsome and delicious meal! I'd love to try it!

  19. Coconut in soup is one of my favourite things!!
    And even with the turmeric fad, I can't seem to find it fresh!

  20. this looks amazing – and catfish is one of my fave fish varieties

  21. Wow, the food sounds very interesting. I actually haven’t tried that kind of food and I have just heard about the Cambodian Hot and Sour Coconut Soup with Catfish. It actually looks very tempting and luscious. I haven’t been to Cambodia, and this is something I should try when I get the chance. Thank you for sharing all the ingredients need for this as well.

  22. This recipe is extremely similar to the indian coastal fish culinary style . Except the lime leaves and lemongrass the recipe is over all the same here. We use the five spices( cardamom , cinnamon etc) from south east ( java) to give it a hotter taste.

  23. Wow this looks like a wonderful recipe. I didn’t know Cambodian food was so nutritious. This dish while time consuming, would be such a treat to make.

  24. Wow! This post is saturated with amazing information. For someone being so picky about half the things you wrote about, it made me want to try. Lol! I ended up saving the recipe!

  25. I have never tried out any Cambodian cuisine but this looks really nice. Thanks for the detailed instructions, I should try this out.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

This page may contain affilate links. See full disclosure policy here.