Zaru soba, or cold soba noodles, is a Japanese dish of cold buckwheat noodles served on a bamboo tray called a zaru with a savory sauce called soba tsayu and sides like pickled ginger, scallions, and sesame seeds. This light Japanese dish is the perfect midweek dinner. The noodles cook in just five minutes and the three-ingredient soba tsayu can be made a week in advance. For those warm days when you don’t feel like doing much cooking, this traditional meal comes together in no time at all. With swirls of soba and a satisfying savory sauce, sipping some smooth sake on the side would certainly be a stimulating supper at sundown.

Zaru Soba: Japanese Cold Buckwheat Noodles [Vegan, Gluten-Free]

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Dipping sauce will serve 8


For the Mizu Dashi (Kombu Seaweed Broth):

  • 4 cups water
  • 12-inch piece of kombu seaweed

For the Kaeshi (Soba Sauce Base):

  • 1/4 cup mirin
  • 1/4 cup sugar
  • 1 1/2 cups soy sauce or tamari

For Assembly and Serving:

  • 3.5 ounces buckwheat soba noodles per person (see notes)
  • Sliced green onions
  • Wasabi paste
  • Grated ginger
  • Pickled ginger
  • Toasted sesame seeds
  • Sliced nori seaweed


To Make the Mizu Dashi:

  1. Place the water in a glass container. Break the kombu into large pieces and place in the water. Cover the container and place in the refrigerator overnight to soak. Alternatively, you can let the kombu soak at room temperature for 30 minutes if time is an issue. Either way, once it is done soaking, pour the water and kombu into a saucepan and bring to a simmer. Remove the kombu, and either discard it or use in another recipe. The broth will keep in the refrigerator, covered, for up to a week.

To Make the Kaeshi:

  1. Pour the mirin into a small saucepan, and bring to a simmer over medium-high heat. Once simmering, turn heat to low and cook for 1 minute. Add the sugar and stir to dissolve. Once the sugar is dissolved, add the soy sauce and stir to combine. Bring to a bare simmer, then remove from heat. The kaeshi can be used immediately, or transferred to a glass container for storage in the refrigerator for up to a week.

To Make the Soba Tsuyu (Noodle Dipping Sauce):

  1. In a medium saucepan, combine 1 cup of kaeshi sauce and 4 cups of the kombu broth. Bring to a simmer, then remove from heat and let cool completely. Once cool, the sauce can be used immediately, or transferred to a glass container for storage in the refrigerator for up to a week.

To Make the Dish:

  1. Bring a large pot of unsalted water to a boil. Once boiling, add enough soba noodles per person, stirring gently to combine. Lower the heat to a simmer and cook 5 minutes, or according to package directions. Reserve some cooking water, then drain noodles into a colander. Pour the noodles back into the pot, place the pot in the sink, and start filling it with cold water from the tap. Let the water fill the pot, then with the water still running, gently swish the noodles around underwater with your hands. The water will overflow, but just keep rinsing the noodles and keep them from running over the top of the pot. Keep rinsing the noodles until they are completely cool and the water runs clear.
  2. To serve, grab a small bundle of noodles from the water and place it on a zaru  (with a plate underneath to catch drips) or plate (make sure to thoroughly drain it).
  3. Make a pile of these bundles on each basket – this technique makes it easier to grab bite-sized portions to dip. Serve at the table with bowls of sliced green onions, wasabi, ginger (fresh grated or picked), toasted sesame seeds, and sliced nori seaweed.
  4. Give each person a small bowl with about 1/2 cup of dipping sauce. Everyone can add whichever toppings to the dipping sauce that they like. Grab a bundle of noodles with your chopsticks, dip them in the sauce briefly, and enjoy. At the end of the meal, you can add the reserved cooking water (called sobayu) to your bowl of sauce to make soup, if desired.


If you're gluten-free, check the packaging on the soba noodles to make sure that they are made with 100 percent buckwheat flour. Some brands mix it with wheat flour.


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