Fish Soup Recipe: Khmer Hot and Sour Coconut Fish Soup (Somlar Machu Ktiss)

Fish Soup: Healthy and Wholesome

Somlar Machu Ktiss (Cambodian Hot and Sour Coconut Fish 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 this Coconut Fish Soup

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 diarrhea.

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.

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.

For this Cambodian Hot and Sour Coconut Fish 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.

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 Fish 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).

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!

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

Cambodian Hot and Sour Coconut Fish Soup with Thai Eggplant and Long Beans (Somlar Machu Ktiss)

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.

4.91 from 11 votes

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Prep Time 20 mins

Cook Time 20 mins

Total Time 40 mins

Course Main Course

Cuisine Cambodian

Servings 4 people

Ingredients

  

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)

Ingredients

• 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

Instructions

 

• 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.
• Add oil to a pot or deep frying pan. Once heated, add kroeung and stir so the kroeung doesn't burn. 
• Once fragrant (about 2 - 3 minutes), add catfish and toss to mix the ingredients. 
• 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. 
• 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.

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. 

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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.

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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. 

Keyword Cambodian hot and sour coconut soup with catfish, Cambodian soup, Cambodian soup recipes, Hot and sour soup recipe

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