u003cstrongu003eWhat can I use instead of water spinach?u003c/strongu003e

Water spinach (also called morning glory or u003cemu003etrakounu003c/emu003e in Khmer) is traditional. If unavailable, you can use regular spinach or bok choy, though the texture will be slightly different.

Beef Water Spinach Sweet Sour Soup

Q: u003cstrongu003eWhat is u003cemu003esamlor machuu003c/emu003e?u003c/strongu003e

u003cemu003eSamlor machuu003c/emu003e is a Khmer term for a category of sour soups. The sourness traditionally comes from tamarind, though other tangy ingredients like tomatoes or pineapple can also be used. This version uses tamarind and beef.

Q: u003cstrongu003eIs this soup gluten-free?u003c/strongu003e

Fish sauce and u003cemu003epahoku003c/emu003e are typically gluten-free, but brands vary. Check the labels of your specific products. This recipe does not contain wheat-based ingredients.

A bowl of Cambodian beef water spinach sweet sour soup with clear tamarind broth, sliced beef, and fresh herbs. — Cambodian beef water spinach sweet sour soup, served hot with fresh herbs and chili.

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Cambodian sour soups, known as samlor machu, are built on a simple idea: a clear broth, a clean tang from tamarind, and fresh herbs added at the very end. This version uses thinly sliced beef and tender water spinach for a soup that feels light but satisfies deeply. The lemongrass and kaffir lime leaves perfume the broth, while the optional pahok adds a savory depth that is unmistakably Khmer.

It comes together in one pot with straightforward steps. If you have a pot, a knife, and a few Southeast Asian pantry staples, you can make this on a weeknight. Serve it hot with steamed jasmine rice, and let the broth do the rest. For more context on how soup anchors Cambodian meals, see our guide to Cambodian soup family meals.

What You Need

The ingredient list is short. The key is freshness in the aromatics. Lemongrass, garlic, and kaffir lime leaves create the base aroma. Tamarind juice provides the sourness. Fish sauce and pahok (fermented fish paste) build the savory backbone. Water spinach cooks in seconds, so have it cut and ready before you start.

Beef sirloin or chuck works best here. Slice it thin so it cooks quickly and stays tender. If you cannot find pahok, you can leave it out, but the soup will taste slightly less traditional. For a similar Cambodian sour soup with a different protein, try our hot sour chicken soup with lotus shoots.

Equipment

Soup pot: To heat the oil, brown the beef, and simmer the broth with aromatics.
Chef’s knife: To chop the garlic, slice the beef, and cut the water spinach into 2-inch lengths.
Cutting board: To prepare the garlic, lemongrass, and water spinach safely.
Measuring spoons: To measure the oil, salt, sugar, tamarind juice, and fish sauce.
Measuring cup: To measure the water.
Wooden spoon or cooking spoon: To stir the aromatics, beef, and greens as they cook.
Ladle: To serve the soup and broth into bowls.

How to Make Cambodian Beef Water Spinach Sweet Sour Soup

Step 1: Build the aromatic base

Heat a large soup pot over medium heat. Add the vegetable oil. When the oil is hot, add the chopped garlic and minced lemongrass. Stir well and cook until fragrant, about 30 seconds to 1 minute. Do not let the garlic brown.

Step 2: Cook the beef

Add the sliced beef to the pot. Season with the salt and sugar. Stir well to combine. Cook the beef, stirring, just until the outside is no longer pink. It will finish cooking in the broth.

Step 3: Add water and kaffir lime leaves

Pour in the water and add the kaffir lime leaves. Raise the heat and bring the water to a bubbling boil.

Step 4: Add water spinach

Once the water is bubbling, add the cut water spinach. Stir it into the broth. The greens will wilt quickly.

Step 5: Season the soup

Season with the fish sauce and tamarind juice. If you are using pahok, add it now and stir well. Taste the broth. It should be tangy from tamarind and savory from fish sauce. Adjust if needed.

Step 6: Finish with herbs and chili

Turn off the heat. Top the soup with the chopped sweet basil, rice paddy herb, and optional chili pepper. Stir gently. Remove the kaffir lime leaves before serving. Ladle into bowls and serve hot with steamed jasmine rice.

Cooking Tips

Slice the beef against the grain. This keeps it tender even with a quick cook.
Have all ingredients prepped before you turn on the stove. The cooking moves fast once the pot is hot.
Taste the broth after adding the tamarind and fish sauce. Different brands of tamarind juice vary in sourness.
Remove the kaffir lime leaves before serving. They are aromatic but not meant to be eaten.

How to Serve

Serve this soup hot in bowls alongside steamed jasmine rice. In a Cambodian home, the soup is not a starter. It sits at the center of the table with rice and maybe one other dish. The broth is spooned over the rice as you eat. If you want more soup recipes to round out the meal, browse our Cambodian soup collection.

Recipe Notes

Pahok is a fermented fish paste used in many Cambodian dishes. It adds a deep savory note. If you cannot find it, you can omit it, but the flavor will be less complex.
Fresh or frozen minced lemongrass works well. If using fresh stalks, remove the tough outer layers and mince only the tender inner part.
Rice paddy herb (ma-om) has a citrus-cumin aroma that is essential to this soup. If unavailable, you can use extra sweet basil, though the flavor will differ.

Frequently Asked Questions

**What is samlor machu?**

Samlor machu is a Khmer term for a category of sour soups. The sourness traditionally comes from tamarind, though other tangy ingredients like tomatoes or pineapple can also be used. This version uses tamarind and beef.

Can I make this soup ahead?

The soup is best fresh, as the water spinach wilts quickly. You can prepare the ingredients ahead and cook the soup just before serving. Leftovers can be stored in the refrigerator for up to 2 days and reheated gently.

What can I use instead of water spinach?

Water spinach (also called morning glory or trakoun in Khmer) is traditional. If unavailable, you can use regular spinach or bok choy, though the texture will be slightly different.

Is this soup gluten-free?

Fish sauce and pahok are typically gluten-free, but brands vary. Check the labels of your specific products. This recipe does not contain wheat-based ingredients.

How spicy is this soup?

The chili pepper is optional. Without it, the soup is gently tangy and aromatic, not spicy. Add as much or as little chili as you like.

Final Thoughts

This soup is a good example of how Cambodian cooking layers flavor without heaviness. The broth stays clear, the beef cooks in minutes, and the herbs go in at the last second so they keep their aroma. Serve it with rice, and you have a meal that feels both simple and complete. Once you try it, you may find yourself keeping lemongrass and tamarind in the kitchen just for this pot.