Thai Vegetable Soup with Coconut Milk, Lime, and Herbs

This Thai-inspired vegetable soup brings rice noodles, colorful vegetables, coconut milk, and red curry paste together in a fragrant, gently spicy broth. Thai soups vary by region and household; this approachable version balances creamy coconut with lime and herbs, and it can be made vegetarian with a suitable curry paste and soy sauce.

Ingredients

6 ounces (170 g) thin rice noodles
1 tablespoon (15 ml) neutral oil, such as canola oil
1/2 cup (75 g) thinly sliced shallots
1 tablespoon (15 g) finely grated fresh ginger
3 garlic cloves (9 g), minced
2 tablespoons (30 g) Thai red curry paste; check the label for shrimp if you need a vegetarian soup
4 cups (960 ml) vegetable broth, preferably lower-sodium
2 makrut lime leaves (about 1 g), lightly torn, optional
1 cup (130 g) carrots, cut into thin coins or half-moons
2 cups (150 g) sliced cremini or shiitake mushrooms
1 cup (150 g) red bell pepper, thinly sliced
1 cup (125 g) green beans, trimmed and cut into 1-inch (2.5 cm) pieces
1 can (13.5 ounces / 400 ml) unsweetened coconut milk
1 tablespoon (15 ml) fish sauce, or soy sauce for a vegetarian version
1 teaspoon (4 g) granulated sugar
2 tablespoons (30 ml) fresh lime juice, plus more to taste
1/2 teaspoon (3 g) fine salt, or to taste
1/4 teaspoon (0.5 g) ground black pepper
1/4 cup (10 g) chopped fresh cilantro
1/4 cup (25 g) thinly sliced scallions
1 small red chile (about 5 g), thinly sliced, optional

Instructions

Prepare the vegetables and aromatics. Slice the shallots, carrots, bell pepper, and green beans, and cut the mushrooms into even pieces. Mince the garlic and grate the ginger. If using makrut lime leaves, tear them once or twice so they release their fragrance in the broth. Keeping the vegetables ready before you start cooking makes it easier to add them in the right order.
Cook the noodles. Bring a saucepan of water to a boil and cook the rice noodles according to the package directions, usually about 4 to 5 minutes for thin noodles. Drain them as soon as they are tender but still slightly firm, since they soften further in hot soup. Divide them among four bowls or set them aside in a bowl with a little water so they do not stick together.
Build the curry base. Warm the oil in a large soup pot over medium heat. Add the shallots and cook for about 2 minutes, stirring until softened but not browned. Stir in the ginger, garlic, and curry paste, then cook for 1 minute. Keep the mixture moving; curry paste should become aromatic, not scorch or stick to the bottom of the pot.
Simmer the firm vegetables. Pour in the vegetable broth and add the torn lime leaves, if using. Stir to loosen any curry paste from the pot. Add the carrots and green beans, bring the broth to a gentle simmer, and cook uncovered for 5 minutes. A steady simmer is better than a hard boil, which can make the broth reduce too quickly.
Add the mushrooms and pepper. Stir in the mushrooms and bell pepper. Simmer for 7 minutes more, or until the carrots are just tender and the beans are cooked but still hold their shape. If you prefer very soft vegetables, simmer for another 2 to 3 minutes; for a crisper texture, begin checking a minute or two earlier.
Finish the broth. Lower the heat and stir in the coconut milk, fish sauce or soy sauce, and sugar. Warm gently for about 3 minutes, stirring occasionally. Avoid a vigorous boil after adding the coconut milk, as prolonged boiling can make the broth look separated. Remove the lime leaves, then mix in the lime juice, salt, and black pepper. Taste and adjust the lime, salt, or curry paste gradually.
Serve. Ladle the soup and vegetables over the noodles. Top with cilantro, scallions, and sliced chile if desired. Serve while hot, with extra lime wedges at the table so each person can adjust the broth to taste.

Tips

Choose curry paste thoughtfully. Thai red curry paste brings chile, aromatics, and seasoning, but brands vary in heat and some contain shrimp. For a vegetarian or vegan soup, read the ingredient label and select a paste without shrimp or fish products. If your paste is salty, start with less soy sauce or fish sauce and add more after tasting.
Use a practical lime-leaf substitute. Makrut lime leaves add a distinct floral citrus scent and can be hard to find. If unavailable, omit them and add about 1 teaspoon (2 g) finely grated lime zest with the coconut milk. Zest gives a bright citrus note, though it will not fully reproduce the leaf’s fragrance.
Keep the vegetables in even pieces. Thin, similar-sized carrot pieces cook at roughly the same rate as the green beans. Cut denser vegetables smaller than softer ones, and add delicate vegetables later. This avoids a pot where some pieces are mushy while others remain undercooked.
Season in stages. Curry paste, broth, and fish sauce or soy sauce can all bring salt. Use lower-sodium broth where possible, then adjust the soup at the end with lime juice and salt. A squeeze of lime can make the flavors taste more balanced without needing to add much extra seasoning.

Serving Suggestions

Serve the soup as a complete lunch or a light dinner, with noodles in each bowl and plenty of vegetables and broth. A side of jasmine rice is useful for soaking up the coconut curry broth, though it is optional when the bowls already contain rice noodles. Keep lime wedges, cilantro, scallions, and sliced chile on the table so diners can finish their servings individually.

For a larger meal, pair the soup with a simple cucumber salad or steamed greens. If serving it as part of a shared spread, offer smaller bowls alongside a rice dish and a mild vegetable side. The broth is flavorful and gently creamy, so a crisp, lightly dressed side provides a pleasing contrast. Keep any extra herbs and lime separate until serving; they taste freshest when added at the last moment.

Variations

Make it fully vegetarian or vegan: Use vegetable broth, a curry paste that contains no shrimp or fish ingredients, and soy sauce or a vegetarian mushroom-based seasoning instead of fish sauce. Check the labels on packaged curry paste and broth, since ingredients differ. The broth will still be savory, although fish sauce has a particular briny depth that soy sauce does not exactly duplicate.

Swap the vegetables: Broccoli florets, sliced zucchini, baby corn, napa cabbage, or thinly sliced bok choy work well. Add vegetables according to how quickly they cook: firm broccoli can go in with the carrots, while zucchini, cabbage, and bok choy are best added during the final few minutes. Aim for about 4 cups (roughly 500 to 600 g) of vegetables in total so the soup remains brothy.

Adjust the richness and heat: For a lighter broth, replace up to half of the coconut milk with additional vegetable broth. The result will be less creamy and somewhat less rich. To make it hotter, add sliced chile at the table or stir a little extra curry paste into a ladleful of hot broth before mixing it into the pot. Adding paste directly to a finished pot can create concentrated spicy pockets.

Change the noodles: Wide rice noodles, wheat noodles, or cooked rice can replace thin rice noodles. Follow the package directions for other noodles and cook them separately when possible; noodles simmered in the soup absorb broth and can become too soft. If using cooked rice, place it in bowls and ladle the soup over it just before serving.

Storage and Reheating

For the best texture, store the noodles separately from the soup. Let the soup cool briefly, then refrigerate it in a covered container within 2 hours of cooking. Keep the noodles in another covered container, ideally with a spoonful of water to help prevent sticking. The soup keeps for 3 to 4 days in the refrigerator; cooked noodles are best used within about 3 days.

Reheat only the amount you plan to eat in a saucepan over medium-low heat, stirring occasionally until steaming hot throughout. USDA FSIS guidance is to reheat leftovers to 165°F (74°C); check the center with a food thermometer. Avoid boiling the coconut broth hard, because it may separate. Add a splash of broth or water if it has thickened, and refresh the flavor with lime juice after reheating. Warm the noodles separately in hot water, drain, and add them to the bowls. Freeze the soup without noodles for up to 2 months for best quality; thaw it in the refrigerator before reheating. Coconut milk may look slightly grainy after freezing, but gentle stirring as it warms usually brings the broth back together.

Frequently Asked Questions

Is this Thai vegetable soup spicy?

It is mildly to moderately spicy with the suggested 2 tablespoons of red curry paste, but heat varies considerably by brand. Start with 1 tablespoon if you are sensitive to chile, then taste the broth before adding more. You can serve sliced fresh chile separately for people who want extra heat without making the whole pot spicier.

Can I make the soup without coconut milk?

Yes. Replace the coconut milk with an equal amount of vegetable broth for a lighter, clearer soup. It will lose the creamy texture and coconut flavor, so taste the broth after the swap and adjust the curry paste, lime, and salt as needed. A small amount of unsweetened oat cream can add some body, but it will change the flavor and is not a traditional substitute.

Can I make it ahead?

Yes. Make the broth and vegetables up to 3 days ahead and refrigerate them promptly in a covered container. Cook the noodles closer to serving time, or store them separately so they do not absorb the broth. Reheat the soup gently until it reaches 165°F (74°C), then add fresh lime juice and herbs just before serving.

Why did my coconut broth separate?

Coconut milk can separate when it is boiled vigorously or heated for a long time. The soup is generally still usable; lower the heat and stir gently to bring the broth back together as much as possible. Next time, keep the soup at a gentle simmer before adding the coconut milk and warm it through without letting it boil hard.

Can I use frozen vegetables?

Yes. Frozen green beans or mixed vegetables are convenient, but they can release water and soften faster than fresh vegetables. Add them near the end of the simmer and cook just until hot and tender, following package guidance if the pieces are large. There is no need to thaw them first, though adding them frozen may briefly slow the simmer.

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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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