Kamo Nanban Soba (Soba Noodle Soup with Duck and Seared Leeks)
Chewy buckwheat soba in a clear, savory dashi broth, topped with crisp-skinned, fully cooked, tender duck breast and sweet, charred leeks. The duck fat that renders from the breast flavors the leeks, and the leeks lend their sweetness to the soup.
- Prep
- 25 min
- Cook
- 38 min
- Wait
- 23 min
- Total
- 1 hr 26 min
- Makes
- 4 large bowls
Steps
Before you start
- Take the duck out of the fridge 15 minutes before cooking. Pat it very dry so the skin crisps.
- Have the dashi ready. Use homemade, or stir 2 teaspoons of dashi granules into 5 cups (1.2 L) of hot water.
- Start the duck in a cold pan. This renders the fat slowly and keeps the meat tender, so don't preheat the pan.
- Check the soba package for cooking time. Most brands take 4 to 6 minutes. Drain them the moment they're ready, because overcooked soba turns mushy.
- The duck is cooked to a safe internal temperature of 165°F (74°C), so use an instant-read thermometer rather than relying on time alone.
Prep duck and leeks
- Pat the duck breasts completely dry with paper towels.
- With a sharp knife, score the skin in a ½-inch (1 cm) crosshatch, cutting through the skin and fat but not into the meat.
- Season all over with the ½ teaspoon kosher salt.
- Cut the leeks into 1½-inch (4 cm) lengths, rinse them well between the layers, and drain.
- Slice the scallions thinly on a diagonal.
- Let the seasoned duck sit at room temperature.
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Ready when: Skin looks dry and the crosshatch is clean and even
Tip: Dry skin is the key to crispness. Pat it again just before it goes in the pan.
Render the skin
- Place the duck skin-side down in a cold 12-inch (30 cm) skillet and set it over medium-low heat.
- Cook without moving for 9 to 10 minutes.
- The fat will slowly melt and pool in the pan.
- If the fat is more than ⅛ inch deep, spoon off the excess into a heatproof bowl and save it.
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Ready when: Skin is deep golden brown and crisp, with most of the fat rendered out and the layer under the skin thin
Tip: If the skin sizzles hard or smokes, lower the heat. Fast browning leaves the fat underneath unrendered.
Flip and cook through
- Flip the breasts and cook the meat side over medium heat for 6 to 8 minutes, turning the heat down to medium-low if the pan smokes.
- Insert an instant-read thermometer sideways into the thickest part.
- Cook until it reads 165°F (74°C).
- Transfer the duck skin-side up to a cutting board.
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Ready when: Thermometer reads 165°F (74°C) in the thickest part and the juices run clear
Tip: Duck breasts vary a lot in thickness, so trust the thermometer, not the timer. Check the thickest breast.
Rest duck, boil water
- Leave the duck to rest, uncovered, so the skin stays crisp.
- Meanwhile, pour all but 1 tablespoon of the fat out of the skillet into a heatproof bowl and leave the skillet on the counter.
- Bring 12 cups (2.8 L) of unsalted water to a rolling boil in the large pot over high heat.
- Don't cook the noodles yet.
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Ready when: Water is at a full rolling boil; duck has rested at least 8 minutes
Tip: Do not cover the duck with foil, because trapped steam softens the skin.
Sear the leeks
- Return the skillet with the 1 tablespoon of duck fat to medium-high heat.
- Add the leek pieces cut-side down in a single layer, working in two batches if needed.
- Cook, turning once, for about 5 minutes total, until browned in spots and tender when poked with a knife.
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Ready when: Leeks have charred, golden-brown spots and a knife slides in easily
Tip: Keep the pieces whole so the layers stay together. Don't stir constantly, or they won't brown.
Simmer the broth
- In the 3-quart (3 L) saucepan, combine the dashi, soy sauce, and mirin.
- Add the seared leeks.
- Bring to a gentle simmer over medium heat, then simmer for 6 minutes.
- Taste the broth; it should be savory and gently sweet.
- If it's too salty, add a splash of water.
- If it's flat, add 1 teaspoon more soy sauce.
- Turn the heat to low to keep it hot.
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Ready when: Broth is steaming with small bubbles at the edges and smells sweet and savory; leeks are soft
Tip: Don't boil hard, because a rolling boil dulls the dashi's delicate flavor.
Boil the soba
- Add the soba to the boiling water and stir gently to separate the strands.
- Cook for 4 to 5 minutes, or according to the package, adjusting the heat to avoid boil-overs.
- Drain in a colander as soon as the noodles are tender but still pleasantly chewy.
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Ready when: A strand bitten in half has no hard white core and still has some chew
Tip: Cook soba in unsalted water. Plenty of water prevents the noodles from clumping.
Rinse the noodles
- Right away, rinse the drained soba under cold running water for about 30 seconds, rubbing and gently squeezing the strands with your hands to wash off the surface starch.
- Drain well.
- If you want them hot, dip the noodles in a strainer into just-boiled water for 10 seconds, then drain again.
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Ready when: Noodles feel smooth, not slimy or sticky, and are no longer warm
Tip: Skipping the rinse makes the broth cloudy and the noodles gummy.
Slice and assemble
- Slice the duck against the grain into ¼-inch (6 mm) slices.
- Divide the noodles among 4 deep bowls.
- Ladle the hot broth over the noodles, dividing the leeks evenly.
- Fan the duck slices on top, skin-side up, and scatter with the scallions.
- Sprinkle with shichimi togarashi if you like.
- Serve immediately.
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Ready when: Duck slices are cooked through with crisp skin; broth is steaming hot
Tip: Place the duck on top just before serving. If it sits in the broth, the skin turns soft.
Good to know
Tips
- Save the leftover duck fat. It's wonderful for roasting potatoes or frying eggs, and keeps in the fridge for a month.
- Cook the duck first and the soba last. Soba is best eaten within a couple of minutes of draining and rinsing.
- Slice duck against the grain with a very sharp knife so each piece is tender and the skin stays attached.
- Season the broth just before serving, since flavors concentrate as it simmers. It should taste slightly bolder than you'd drink on its own, because the noodles dilute it.
Make ahead
Make the broth up to 3 days ahead and refrigerate it in a covered container. Reheat it gently until steaming. Cook, slice, and refrigerate the duck up to 1 day ahead, but boil and rinse the soba just before serving.
Storage & reheating
Store broth, sliced duck, leeks, and noodles in separate airtight containers. Soba noodles keep in the fridge for 1 day, and the other parts keep for up to 3 days. Do not store the noodles in the broth. Reheat the broth on the stove until steaming. Warm the duck briefly in a hot skillet until it reaches 165°F (74°C) again. Refresh the noodles in hot water for 15 seconds. The broth (without noodles) freezes for up to 2 months. Thaw it overnight in the fridge. Cooked soba and duck do not freeze well.
Substitutions
- dashi → Instant dashi granules (2 tsp) dissolved in 5 cups (1.2 L) hot water. Convenient and widely available; check the salt content and adjust the soy sauce if the broth tastes too salty.
- mirin → 3 tbsp dry sherry or sake plus 1 tbsp sugar. Gives similar sweetness; stir until the sugar dissolves before simmering.
- medium leeks → Thick Japanese negi, or the white parts of 6 to 8 fat scallions. Negi is closest to the traditional dish. Scallions need only 2 to 3 minutes of searing.
- dried soba (buckwheat) noodles → Udon or dried 100% buckwheat soba for gluten-free (check the label). Udon is chewier and takes longer to cook, so follow the package. Many soba brands contain wheat flour, as does the soy sauce; use tamari for gluten-free.