Cambodian Chicken Sour Soup (Samlor Machu)

Cambodian chicken sour soup, often called samlor machu, is a flexible family of soups built around a bright sour broth, tender chicken, vegetables, and fresh herbs. This version balances tamarind with lemongrass, galangal, tomato, and pineapple, so it tastes lively and savory rather than simply sharp.

Ingredients

1 tablespoon neutral oil (15 ml), such as vegetable or canola oil
2 stalks lemongrass (about 60 g), tough outer layers removed, tender lower portions bruised and cut into 3-inch pieces
1-inch piece fresh galangal (15 g), thinly sliced; ginger is a practical substitute, though it gives a warmer, less piney flavor
4 makrut lime leaves (about 2 g), torn once; if unavailable, use 1 teaspoon finely grated lime zest (2 g), added near the end
2 medium shallots (about 60 g), thinly sliced
3 garlic cloves (about 9 g), lightly crushed and chopped
6 cups low-sodium chicken broth or water (1.4 L)
1 1/2 pounds boneless, skinless chicken thighs (680 g), cut into bite-size pieces
2 tablespoons tamarind concentrate (30 ml), or 3 tablespoons tamarind pulp softened in hot water and strained (45 ml)
1 tablespoon fish sauce (15 ml), plus more to taste
1 teaspoon granulated sugar (4 g), to round the sourness
1 cup fresh pineapple chunks (165 g), cut into bite-size pieces
2 medium ripe tomatoes (about 300 g), cut into wedges
8 ounces water spinach (225 g), trimmed and cut into 3-inch lengths; substitute baby spinach or chopped Swiss chard
1/2 teaspoon fine salt (3 g), or to taste, depending on the broth and fish sauce
1/4 cup chopped sawtooth coriander or cilantro (10 g), for finishing
2 tablespoons chopped Thai basil leaves (5 g), for finishing
1 lime (about 60 g), cut into wedges for serving

Instructions

Prepare the ingredients. Set aside about 25 minutes to trim and cut the chicken, wash and cut the water spinach, and slice the aromatics and vegetables. Bruise the lemongrass with the flat side of a knife or a small pan; opening the stalk helps release its fragrance into the broth. If using tamarind pulp rather than concentrate, cover it with a little hot water, mash it, and strain out the seeds and fibers while you prep.
Start the aromatic broth. Heat the oil in a large pot over medium heat. Add the lemongrass, galangal, lime leaves, shallots, and garlic. Stir for about 2 minutes, just until fragrant and softened; do not let the garlic brown. Pour in the chicken broth or water, then bring it to a gentle boil. Lower the heat and simmer uncovered for 6 minutes to infuse the liquid.
Cook the chicken. Stir in the chicken pieces, tamarind, fish sauce, and sugar. Return the broth to a gentle simmer and cook for 15 minutes, stirring once or twice so the pieces cook evenly. Avoid a hard rolling boil, which can make the broth cloudy and the chicken less tender. Check the largest piece with a food thermometer: USDA FSIS says poultry must reach a safe minimum internal temperature of 165°F (74°C).
Add the fruit and tomatoes. Add the pineapple and tomato wedges and simmer for 9 minutes. The tomato should soften but mostly hold its shape, while the pineapple warms through and gives the broth a light fruity edge. Taste the liquid before adding salt, because fish sauce and packaged broth can already contribute plenty.
Finish with greens and balance the flavor. Add the water spinach and simmer for 3 minutes, just until tender but still green. If using baby spinach, cook it only until wilted, usually about 1 minute. Taste the broth: add salt if it needs savoriness, a little more fish sauce for depth, or a small spoonful of tamarind if you want a sharper sour note. If it is too tart, add a pinch of sugar rather than more broth.
Garnish and serve. Turn off the heat and stir in the sawtooth coriander or cilantro and Thai basil. Remove the lemongrass pieces, galangal, and lime leaves before serving, or leave them in the pot and tell diners not to eat them. Ladle the soup into bowls with plenty of chicken, greens, tomato, and pineapple, and offer lime wedges at the table.

Tips

Adjust tamarind gradually. Tamarind products vary in strength, so start with the listed amount and taste after the vegetables cook. Concentrate is convenient; strained pulp can taste rounder and less intense. Add more in small increments, since it is easier to sharpen the soup than to correct an overly sour pot.
Keep the aromatics recognizable. Bruise the lemongrass rather than finely chopping it, and cut galangal into slices that are easy to spot and remove. These ingredients perfume the broth, but their fibrous texture is not pleasant to chew. If using ginger instead of galangal, use the same amount and expect a warmer, less citrusy aroma.
Use the right greens for the timing. Water spinach has crisp stems that need a few minutes; tender spinach needs much less. Chard can take 4 to 5 minutes depending on the thickness of its stems, so add the chopped stems before the leaves. This prevents limp leaves while the stems are still hard.
Choose a broth base to suit your pantry. Water makes a clean-tasting soup that lets the sour aromatics stand out; low-sodium chicken broth makes it fuller. Avoid strongly salted broth until you have balanced the tamarind and fish sauce, and season at the end.

Serving Suggestions

Serve the soup hot in individual bowls, with steamed jasmine rice on the side or a small mound of rice in each bowl. Rice softens the sour-salty broth and makes the meal more substantial. Keep lime wedges, extra chopped herbs, and fish sauce at the table so each person can adjust a portion without changing the whole pot. For a simple meal, add sliced cucumber or a plate of blanched greens; their mild flavors sit well beside the sharp, aromatic soup.

For a more traditional herb note, use sawtooth coriander if you can find it at a Southeast Asian grocery store. Cilantro is easier to find and works well, but its flavor is milder and less distinctive. Serve the soup as a main course with rice or as one dish in a larger meal alongside grilled fish, vegetables, and other shared plates.

Variations

Samlor machu is not one fixed recipe: Cambodian households and regions vary the souring agent, vegetables, herbs, and protein. Some versions use tamarind, while others may use lime, green mango, or another sour ingredient. This recipe uses tamarind for a steady, rounded acidity and pineapple for a gentle sweetness; omit the pineapple if you prefer a less fruity broth, then adjust the sourness and seasoning at the end.

For a deeper savory flavor, add 1 to 2 teaspoons (5 to 10 ml) of prahok, a fermented fish paste used in Cambodian cooking, when you add the chicken. It can be hard to find and has a pronounced, salty aroma, so start small and reduce or omit the fish sauce to taste. If you cannot find prahok, the fish sauce in the recipe is a practical substitute, though the soup will lack prahok’s distinctive fermented depth.

You can replace chicken thighs with bone-in chicken pieces, but allow extra simmering time and check the thickest part without touching the bone for 165°F (74°C). For a meat-free variation, use firm tofu and vegetable broth; simmer the aromatics as directed, add tofu with the tomatoes, and use soy sauce or a vegetarian fish-sauce alternative for savory seasoning. This changes the classic chicken version, but the sour broth still works well with vegetables.

Storage and Reheating

Refrigerate leftover soup within 2 hours of cooking in a shallow, covered container. It keeps for 3 to 4 days in the refrigerator. The broth may taste slightly more intense the next day as the aromatics continue to infuse; remove any large lemongrass or galangal pieces before storing if you do not want that flavor to deepen.

Reheat only the portion you plan to eat, on the stovetop over medium heat, stirring occasionally until it reaches 165°F (74°C). Check with a food thermometer, especially when reheating chicken pieces. You can also microwave a serving in a covered, microwave-safe bowl, stirring midway through and checking several spots for even heating. If the soup has thickened, loosen it with a splash of water or broth. For longer storage, freeze in airtight containers for up to 2 to 3 months for best quality; thaw overnight in the refrigerator and reheat to 165°F (74°C). Greens soften after freezing, so add fresh greens when reheating if texture matters to you.

Frequently Asked Questions

What makes Cambodian chicken sour soup sour?
Tamarind is the souring ingredient in this version. It gives the broth a fruity, rounded tang that pairs with fish sauce and herbs. Cambodian sour soups have many household and regional variations, so lime, green mango, or other sour ingredients may be used in other versions.

Can I make the soup without tamarind?
Yes. Lime juice can provide acidity, but it tastes brighter and less fruity than tamarind. Start with 1 tablespoon (15 ml) of lime juice stirred into the finished soup, taste, and add more gradually. Do not boil the soup for a long time after adding lime, because its fresh flavor will fade.

Where can I find galangal, makrut lime leaves, and water spinach?
Look in Southeast Asian grocery stores, where these ingredients are often sold fresh or frozen. Frozen galangal and lime leaves are useful pantry options. If you cannot find them, use ginger for galangal, a little lime zest for the leaves, and baby spinach for water spinach; each substitute changes the flavor or texture slightly but still makes a good soup.

Can I prepare Cambodian chicken sour soup ahead?
You can slice the aromatics and vegetables and cut the chicken a day ahead, keeping the chicken covered separately in the refrigerator. The soup itself can also be cooked ahead and refrigerated, though the greens will soften as they sit. For the freshest texture, prepare the broth and chicken in advance, then reheat it thoroughly and add the greens shortly before serving.

How do I keep the chicken from drying out?
Cut the thighs into fairly even bite-size pieces, keep the broth at a gentle simmer, and begin checking the largest piece at the end of the stated cooking time. Chicken must still reach 165°F (74°C) for safety, so use a thermometer rather than relying only on color. Thigh meat is generally more forgiving than breast meat if the soup simmers a little longer.

Is this soup very spicy?
No, the recipe as written is aromatic and sour rather than hot. For heat, add 1 thinly sliced bird’s-eye chile (about 5 g) with the shallots, or serve sliced chile separately so everyone can choose. Chile strength varies, so add a small amount first and taste before adding more.

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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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