Kalguksu (Korean Knife-Cut Noodle Soup with Chicken, Zucchini and Potato)
Chewy wheat noodles in a clean, savory anchovy-kombu broth with tender chicken, silky zucchini and potato, finished with ribbons of egg and a spoonful of garlicky soy-sesame sauce. It's comforting, quick for a from-scratch broth, and ready in about an hour.
- Prep
- 25 min
- Cook
- 38 min
- Total
- 1 hr 3 min
- Makes
- 4 large bowls (about 2 cups noodles and 1½ cups broth each)
Steps
Before you start
- Buy fresh or frozen kalguksu noodles (thick, flat, knife-cut style) at a Korean market; udon or dried kalguksu noodles also work (see substitutions).
- Large dried anchovies (about 3 inches / 8 cm) make the cleanest broth. Pull off the heads and split the bellies to remove the dark guts, which taste bitter.
- Start the broth first and cut the vegetables and chicken while it simmers; the whole recipe takes about 1 hour.
- Cook the noodles in a separate pot of water so the soup stays clear rather than cloudy and starchy.
Prep the anchovies
- Pinch the heads off the anchovies and split each body open along the belly.
- Pull out and discard the dark gut line.
- Wipe the kombu with a damp cloth to remove grit, but do not rinse off the white powder, which carries flavor.
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Ready when: Anchovies are clean, with no dark innards or heads.
Tip: Skipping the gut removal makes the broth bitter and cloudy.
Toast the anchovies
- Set the 4-quart soup pot over medium heat.
- Add the cleaned anchovies and toast, stirring often, for 2 minutes to remove any fishy smell.
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Ready when: Anchovies smell nutty and toasty and look slightly darker and dry.
Tip: Do not let them brown or scorch; scorched anchovies make the broth bitter.
Simmer the broth
- Add the 1900 ml (8 cups) cold water, kombu and onion half to the pot.
- Raise the heat to high and bring to a boil, about 8 minutes.
- As soon as the water boils, or after 10 minutes at most, lift out and discard the kombu.
- Lower the heat to medium-low, partially cover and simmer gently for 12 more minutes.
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Ready when: Broth is pale golden and smells savory and slightly sweet; the surface shows gentle bubbles, not a hard boil.
Tip: Boiling kombu longer than 10 minutes makes the broth slimy and bitter.
Cut chicken and vegetables
- While the broth simmers, slice the chicken into ¼-inch (6 mm) strips, peel and slice the potato into ⅛-inch (3 mm) half-moons, cut the zucchini into ⅛-inch (3 mm) half-moons, and thinly slice the soup onion.
- Slice the serving scallions on a diagonal.
- Keep each item in its own pile; they go into the pot at different times.
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Ready when: Potato slices are thin enough to bend slightly, so they cook through in about 8 minutes.
Tip: Slice potato evenly and thinly or it will stay hard in the center while the other ingredients are done.
Strain the broth
- Set a fine-mesh strainer over a bowl or clean pot and pour the broth through it.
- Discard the anchovies and onion.
- Wipe out the pot, return the broth to it and keep it warm over low heat.
- You should have about 1.6 L (6½ cups).
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Ready when: Broth is clear with no bits of anchovy floating in it.
Mix the seasoning sauce
- In a small bowl, stir together the 30 ml (2 tbsp) soy sauce, gochugaru if using, grated garlic, chopped scallion, sesame oil and sesame seeds.
- Set aside for diners to spoon onto their soup.
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Ready when: Sauce looks loose and speckled with chopped scallion and chili.
Boil and rinse noodles
- Bring the 2800 ml (12 cups) water to a rolling boil in the large pot over high heat.
- Add the noodles, stir to separate, and cook 3 to 4 minutes (follow the package time, if different).
- Drain in a colander and rinse well under cold running water, rubbing gently, to wash off the surface starch.
- Drain well.
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Ready when: Noodles are chewy with no raw flour center when you bite one, and feel slippery after rinsing.
Tip: Don't skip the rinse; leftover starch turns the soup thick and cloudy.
Cook chicken and potato
- Bring the strained broth to a steady simmer over medium heat.
- Add the potato, chicken and sliced onion.
- Simmer for 8 minutes, skimming off any foam from the surface.
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Ready when: Chicken is opaque with no pink and reads 165°F (74°C); a potato slice is tender when poked with a fork.
Tip: Keep it at a gentle simmer; a hard boil toughens chicken and clouds the broth.
Add zucchini and season
- Add the zucchini, 1 tbsp soy sauce and 1 tsp salt.
- Simmer 3 minutes, then taste the broth and add more salt, ¼ tsp at a time, until it tastes savory enough to eat with plain noodles (the sauce adds more salt later).
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Ready when: Zucchini slices look translucent and yield easily to a spoon but still hold their shape.
Tip: Season now, not before; the broth reduces slightly and the anchovies vary in saltiness.
Stir in the egg
- Bring the soup to a gentle bubble.
- Slowly pour the beaten eggs in a thin stream while stirring the soup in one slow circle.
- Stop stirring and let the eggs set for 30 seconds, then break them into ribbons with a gentle stir.
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Ready when: Egg forms soft, fully opaque ribbons (160°F / 71°C) with no runny liquid.
Tip: Pouring slowly into a gently moving broth makes ribbons instead of clumps.
Assemble and serve
- Divide the rinsed noodles among 4 large bowls.
- Ladle the hot soup, chicken and vegetables over the noodles.
- The hot broth will warm the noodles within a minute.
- Top with scallions and crumbled gim, and serve right away with the seasoning sauce on the side.
- Each diner stirs in 1 to 2 tsp to taste.
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Ready when: Noodles are fully submerged and steaming, with a mix of chicken and vegetables in every bowl.
Tip: Serve immediately; noodles continue to absorb broth and soften the longer they sit.
Good to know
Tips
- Always boil and rinse the noodles separately to keep the broth clear; if you cook them in the soup, use a wider pot and expect a thicker, starchier broth.
- Keep the broth at a gentle simmer after straining; boiling hard makes the egg and chicken tough and the soup cloudy.
- Taste the broth before adding salt; dried anchovies and soy sauce vary a lot in saltiness.
- For a spicier bowl, stir in extra gochugaru or add one sliced green chili with the zucchini.
Make ahead
"Make the strained broth up to 3 days ahead and refrigerate it. Slice the vegetables and chicken the day before and store them separately in the refrigerator. Mix the seasoning sauce up to 3 days ahead. Cook the noodles just before serving."
Storage & reheating
"Store the soup and noodles separately in airtight containers. Refrigerate the soup up to 3 days; noodles up to 2 days tossed with a little sesame oil. Freeze the broth (without noodles or egg) up to 2 months. Reheat the soup on the stove over medium heat until steaming and chicken reaches 165°F (74°C), then pour over noodles that have been rinsed in hot water. Do not leave room-temperature soup out for more than 2 hours."
Substitutions
- fresh kalguksu noodles → Dried kalguksu noodles, fresh udon, or fettuccine. Cook dried noodles per the package, usually 5 to 8 minutes; fettuccine will be less chewy but works in a pinch.
- large dried anchovies → Dried shiitake mushrooms (4) plus extra kombu, or 2 packets Korean anchovy broth tablets. The mushroom version is vegetarian-friendly (also omit the chicken); tablets are saltier, so reduce the salt.
- boneless, skinless chicken thighs → Littleneck clams (1 lb / 450 g) or firm tofu. Add clams in step 8 until they open, about 4 minutes; discard any that stay shut. Tofu needs only 2 to 3 minutes.
- waxy or all-purpose potato → Sweet potato. Slice the same thickness; it gives a sweeter broth and cooks in about the same time.