Easy 20-Minute Soba Noodle Soup (Japanese Kake Soba)

Take a culinary journey and explore the depths of Japanese flavors with soba noodle soup. Brimming with warm and flavorful soba noodles, served in an umami-rich dashi soup accompanied by various toppings for you to enjoy!

Have you ever wanted to make the perfect bowl of soba noodle soup?

While it may seem intimidating, I'll show you how easy it is. From picking out your ingredients to finishing up, explore the world of Japanese-style noodle soup with me!

This recipe is for you if:
• You love Japanese soba noodles.
• You want to make simple or hearty soba noodle soup.
• You want to make soba noodle soup from scratch.

In addition to the recipe, you will get info about soba noodles, details of ingredients, how to make dashi and soup, and vegan options.

Let's get started!

Jump to:

• About this recipe
• What is Mentsuyu?
• 📋 Ingredients
• 🔪Instructions
• Topping Variation
• Kake Soba Topping Examples
• Variations of soba noodle soups
• Thanks For Stopping By!
• 📖 Recipe
• 💬 Comments

About this recipe

• Authentic Japanese soba noodle recipe
• Many ideas for toppings
• Homemade dashi soup
• Vegan adaptable

What is Mentsuyu?

Soba noodle soup is a traditional Japanese dish prepared by pouring the hot savory broth over boiled soba noodles and then topped with some toppings.

It's a popular quick lunch menu for the on-the-go. You can easily find the noodle stands that serve soba noodle soups (as well as udon noodles) at train stations across the country.

There are many variations of this cozy soup, such as tempura soba and kitsune soba; however, the simplest one is called "Kake soba" with minimum toppings.

I will show you how to make Kake soba in this recipe and introduce various topping ideas in the following.

Toshikoshi soba

The new year is a big family event in Japan, and we have a long-standing tradition of eating a hot bowl of soba noodle soup on New Year's Eve.

It’s called Toshikoshi soba (Toshikoshi means New Year's Eve in Japanese).

Thin and long buckwheat soba noodles symbolize longevity and are thought to bring good health and good luck into the household for the upcoming new year. Topping can be anything, but many people eat it with shrimp tempura as it symbolizes long life and well-being.

I eat Toshikoshi soba for lunch on New Year's Eve, but some people eat it for dinner or right before midnight. Anyway, soba noodles are an icon of Japanese cuisine, enjoyed and cherished by many.

📋 Ingredients

Here are the ingredients (amounts are in the recipe card below).

• Soba noodles: Dried, fresh, or frozen soba noodles are available at grocery stores. I use fresh soba noodles in this recipe.
• Soup: I make dashi (soup stock) from scratch with katsuobushi (dried bonito flakes), kombu (kelp), and niboshi (dried baby sardines), and season with mirin and soy sauce to finish the soup.
• Toppings: Green onions and dried wakame seaweed.

See more details for each in the following.

What are Soba Noodles？

Soba noodles are popular Japanese noodles made by kneading buckwheat flour with water, stretching it out thinly, and cutting it into thin strips. The light gray color is from buckwheat flour.

With their chewy texture and subtle taste, these noodles enhance any soup it's paired with.

You might be able to find dried, fresh, or frozen soba noodles at Asian grocery stores. Having dried noodles is handy, and I usually buy them and keep the stock in my pantry.

Types of Soba Noodles

Historically, soba noodles were crafted from only buckwheat flour and water. But since the grain is gluten-free and difficult to form the noodle, wheat flour is added as a binding agent.

Soba noodles' name is all determined by their wheat flour content, such as

• Juwari Soba (十割そば) - 100% buckwheat flour (gluten-free)
• Nihachi Soba (二八そば) - 20% wheat flour, 80% buckwheat flour
• Gowari Soba (五割そば) - 50% wheat flour, 50% buckwheat flour

The ratio of buckwheat flour should be more than 30% to sell as soba noodles, so if it just says "soba" on the package, it probably includes mostly wheat flour, which is more likely darker color udon.

If you want to try real soba noodles, try Juwari or Nihachi soba. You will enjoy the flavor of buckwheat flour and its texture. By the way, my favorite is Nihachi soba.

If you follow a gluten-free diet, you should pick Juwari.

Ingredients for the soup

Noodle soup is called "mentsuyu" in Japanese. We make it from dashi (soup stock) and season it with soy sauce and mirin.

• Dashi: Katsuobushi (dried bonito flakes), kombu (kelp), niboshi (dried baby sardines)
• Seasoning: Mirin, soy sauce

Dashi is the base of the soup and a key umami flavor.

I use 3 different dashi ingredients in this recipe, but you can make other dashi such as Awase dashi (katsuobushi and kombu), niboshi dashi, or shiitake kombu dashi (vegan dashi).

If making dashi is too much work, you can use instant dashi powder to save time. I always have some instant dashi powder for making miso soup. They are common and convenient items for Japanese cooking.

Soba soup is also used for udon noodles. If you go to a noodle stand at a station in Japan, you can choose either soba noodles or udon noodles, and they pour the same soup over the noodles.

Toppings

As I mentioned, Kake soba is a simple noodle soup topped with one or two ingredients. The popular one is green onions, and I added my favorite wakame seaweed to this recipe.

I will give you more topping options later. If you want to explore, please check out the topping section!

🔪Instructions

Whew, I had a lot to tell you about ingredients. Ok, now, it's finally time to cook! Let me show you how to make soba noodle soup! You can also watch this recipe video.

There are three steps, make a noodle soup, prepare toppings, and finish the soup! Let's dive in!

Step #1 Make a noodle soup

1. Put ingredients: Put katsuobushi, kombu, niboshi (snap the head and remove the guts, watch: how to prepare niboshi), and water in a large saucepan and bring to a boil over medium-high heat.
2. Simmer: When it starts boiling, lower the heat to low and simmer for about 2 minutes. If you check the taste, you can taste the flavorful umami.
3. Add mirin and soy sauce: Add mirin and soy sauce, bring it to a boil again, then remove the pot from heat.
4. Drain: Drain in a colander and remove the dashi ingredients.

The soup is done!

If you do not use it immediately, let it cool down, put it in a glass jar, and store it in the fridge for one week. Or freeze it for long-term storage. Put it in a freezer bag or ice cube tray and store it in the freezer for one month.

Step #2 - Prepare toppings

Chop green onions, and rehydrate dried wakame seaweed.

Step #3 - Boil soba and toppings

Ok, this is the last step. Let's finish and enjoy the flavorful Japanese soup!

1. Boil water: Put water in a large saucepan, bring it to a boil, then put soba noodles.
2. Boil soba noodles: Boil them according to the package directions (4-7 minutes for dry, 1-2 minutes for fresh noodles, for your reference).
3. Drain: Drain in a colander and rinse under cold running water to remove the starch.
4. Serve soba noodles: Prepare a bowl and serve boiled soba noodles.
5. Pour soba soup: Gently pour the warm soup over the noodles.
6. Toppings: Place chopped scallions and wakame seaweed.

Here you go! Once it's served, please eat immediately. Otherwise, the soba noodle soaks up the soup and becomes soggy.

If you like a little spice, sprinkle with shichimi togarashi (Japanese spice blend) and enjoy!

Vegan Adaptable

Dashi is made from katsuobushi and niboshi, and they are fish, so it's not vegan-friendly.

But I have a vegan option for you. You can make vegan Kake soba if you substitute it with vegan dashi: Shiitake Kombu Dashi.

The flavor is milder, but I'm sure you would enjoy the flavor from shiitake and kombu.

What to Do with the leftover dashi ingredients

When you make dashi stock from scratch, you will have the leftover, called dashi gara (leftover dashi). You can make a delicious furikake with it, so don't throw it away!

Finely chop with a food processor, stir fry with soy sauce, mirin, sake, sesame seeds, and maybe a little spice mixture (if you like spices), and you'll have a wonderful furikake.

Go ahead, sprinkle on a bowl of rice, mix in the rice, make onigiri (rice ball), put it on a salad, or use it for seasoning for stir-fried vegetables. So many ways to enjoy it!

Topping Variation

This is the fun part! Various ingredients go well with Kake soba, but I have listed the classic and popular toppings that are easy to prepare.

• Green onions or Scallion
• Wakame Seaweed
• Kamaboko fish cake - A type of fish cake
• Onsen Tamago - A half-boiled egg. Place eggs in boiled water and leave for 15-20 minutes to cook slowly
• Agedama - Pieces of tempura batter
• Spinach - Boil for 1 minute
• Tororo Kombu - Flakes of kombu seaweed
• Aburaage - Thin deep-fried tofu. Bake on both sides with a toaster to make it crispy

And more topping ideas

• Satsuma Age - A type of fish cake
• Natto - Sticky fermented soybeans
• Chikuwa - A type of fish cake
• Kimchi
• Nori sheet

Kake Soba Topping Examples

Which one do you want to try? Here are some examples of servings.

1. Scallions and Wakame Seaweed

Scallions and wakame seaweed are classic toppings that we often see at a soba noodle stand. It's simple, easy, and quick.

2. Onsen Tamago and Kamaboko

Scallions, wakame seaweed, onsen tamago, kamaboko, and agedama on top. This is my favorite one as it has more colors and is so appetizing.

3. Aburaage and Tororo Kombu

Scallions, wakame seaweed, spinach, aburaage, agedama, and Tororo kombu. It looks so delicious. I'm sure you will be full after finishing this special Kake soba.

4. Stir-fried Vegetables

This is not on the list, but if you have some leftover stir-fried vegetables, they can be a great topping for soba noodle soup!

You can try these recipes for toppings:

• Tempeh Stir-fry
• Hijiki Salad (simmered hijiki)
• Atsuage Teriyaki
• Eggplant Teriyaki

Something seasoned with soy sauce or miso paste would go well. Or you can go ahead and experiment with your favorite dish!

Simmer ingredients with the soup

If you feel like eating Kake soba with plenty of vegetables, it's best to cut them and simmer them with the soup.

The photo above is with carrots, shimeji mushrooms, and scallions. Cut vegetables, add them to the soup, then cook for 4-5 minutes until tender.

Here are other vegetables you can try:

• Daikon
• Onion
• Potato
• Kabocha (pumpkin)
• Shiitake mushrooms
• Enoki mushrooms
• Eringi mushrooms
• Komatsuna (green leaf)
• Bok choy
• Napa cabbage
• Sweet potato
• Any leafy greens

My favorite one is mushrooms. Put maitake, shiitake, and eringi in the soup, simmer, and top with scallion. I would be so happy to eat this hearty mushroom Kake soba.

Variations of soba noodle soups

Japanese restaurants offer a wide range of soba noodle soups on their menu - each variety has its unique name. Some of the most popular varieties include:

• Kakiage soba - Kakiage (a type of tempura) on top
• Kitsune soba - Seasoned aburaage (thin deep-fried tofu) on top
• Kake soba - Green onions and wakame seaweed on top
• Chikuwaten soba - Tempura of chikuwa (a type of fish cake) on top
• Tsukimi soba - Raw or half-boiled egg on top
• Tempura soba - Shrimp tempura on top

By the way, if you are familiar with Japanese soba noodles, you might wonder what zaru soba (or mori soba) is. The style is different from Kake soba. It's served cold, and the soup is in a separate bowl, so you eat it by dipping soba noodles in the soup.

Are Soba noodles healthier than Udon noodles?

Buckwheat flour is highly nutritious, so we generally say soba noodles are healthier than udon noodles.

• Soba noodles' Glycemic Index is lower than udon noodles.
• Soba noodles have more dietary fiber than udon noodles.
• Soba noodles have more protein than udon noodles.

If you pay attention to blood sugar levels, soba noodles are more recommended than udon noodles.

But remember, some soba noodles include more flour than buckwheat flour (like 70% flour and 30% buckwheat flour), so in that case, it won't make much difference.

For a gluten-free option, you should select "Juwari soba," which is 100% made from buckwheat flour.

Thanks For Stopping By!

As I mentioned, Kake soba is the simplest noodle soup, but the topping variations are limitless! I hope you will enjoy this authentic recipe!

Thank you for taking the time to read my blog♡ If you’ve tried this recipe(or any other recipe on the blog), please give it a star rating below!

Also, feel free to leave comments if you have any questions. I love hearing from you!

Chef JA Cooks is a Japanese food blog that shares simple and healthy Japanese home cooking recipes including vegan and vegetarian. From traditional Japanese recipes to modern recipes with step-by-step instructions.

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• Nibohsi Dashi

📖 Recipe