Classic Udon Noodle Soup (Kake Udon or Su Udon) is all about simplicity: thick, chewy noodles and a delicate homemade broth deliver a hot bowl of comfort. Enjoy this vegan-adaptable soup as is, or add tempura, fish cake, and vegetables for a more substantial meal.

Japanese bowls containing Classic Udon Noodle Soup called Kake Udon or Su Udon, topped with sliced green onion and shichimi togarashi (Japanese seven spice).

Of all the Japanese noodles, I often turn to udon when I need comfort. To me, these chewy, slippery noodles seem to have a special power to soothe any troubles and satisfy one’s hunger. We eat them anytime, for a quick lunch or a fulfilling dinner. And they are perfect whether hot, cold, or anywhere in between.

I love all kinds of udon dishes, but nothing beats the classic, simple hot udon noodle called Kake Udon (かけうどん). Today, let’s learn more about it and how to make an authentic bowl at home.

Japanese bowls containing Classic Udon Noodle Soup called Kake Udon or Su Udon, topped with sliced green onion, onsen tamago (poached egg), and fish cake slices.

What is Kake Udon?

Kake Udon (かけうどん) is the most basic form of hot udon noodle soup, consisting of udon noodles in a flavorful dashi-based broth. It is inspiring because it celebrates simplicity.

In the Kansai region (Osaka, Kobe, and Kyoto area), this udon noodle soup is called Su Udon (素うどん). The major difference between the Kansai and Kanto (Tokyo) regions lies in the color of the soup broth.

Su Udon’s broth is much lighter in color compared to Kake Udon’s. People in the Kansai region use a light-colored soy sauce called Usukuchi Shoyu (薄口醤油) instead of regular soy sauce.

This simple udon noodle soup can be transformed into something more by changing the seasonings or toppings. For example, you can make Kitsune Udon with inari age (seasoned fried tofu), Nabeyaki Udon with shrimp tempura and various toppings, and Chikara Udon with toated rice cake.

🗾 Did you know? Several regions in Japan are known for udon noodles. The most well-known prefecture is Kagawa in the Shikoku region, followed by Fukuoka in the Kyushu region and Saitama in the Kanto region. Kagawa is known for Sanuki Udon (讃岐うどん), which is characterized by its chewy and elastic noodles and sardine soup stock.

Ingredients for Basic Udon Noodle Soup

  • Udon noodles – Frozen and dried udon noodles are easily accessible outside Japan. You can also make homemade udon noodles from scratch with three ingredients—flour, salt, and water!
  • Noodle soup base (mentsuyu or tsuyu) – I will discuss this in detail in the following section.
  • Toppings of your choice – You can keep it simple with sliced green onions and shichimi togarashi (Japanese seven spice). See more choices below.

How to Make Udon Soup Broth

I’ll share two methods so you have the options depending on the ingredients that are accessible to you.

📝 It’s good to remember each udon bowl requires roughly 300 ml (1¼ cup) of soup broth.

Method 1: Make it from scratch

To make udon soup broth, make dashi (Japanese soup stock) and season it with soy sauce, mirin, (sometimes sake), sugar, and salt. It’s very simple and easy!

Dashi 3 Ways

You can make dashi from scratch with kombu and katsuobushi, which takes about 30 minutes or less. If you want to speed things up, use a dashi packet or dashi powder. For vegetarians/vegans, you can make Vegan Dashi.

Method 2: Make it with noodle soup base (mentsuyu)

If you can buy a bottle of noodle soup base (mentsuyu or tsuyu) at a Japanese or Asian grocery store or from Amazon, you can instantly make udon soup broth by mixing it with hot water. Read the bottle’s instructions carefully, as each brand has a different mentsuyu-to-water ratio.

For those who enjoy soba and udon noodles, I recommend keeping a bottle of mentsuyu in the fridge. You can make noodle soup instantly! You can also make Homemade Mentsuyu.

How to Cook Udon Noodles

Kake Udon-step by step-2

To cook udon noodles, prepare a large pot of water. They already contain salt, so we do not need to salt the water (the same goes for soba noodles). Cook the noodles according to the package instructions. For fresh noodles, see the cooking instructions in my Homemade Udon Noodles recipe.

Why don’t we put the udon noodles directly into the soup broth? Udon noodles release starch and we want to make sure the soup broth is clear and not cloudy due to starch.

Topping Choices

Japanese bowls containing Classic Udon Noodle Soup called Kake Udon or Su Udon, topped with sliced green onion, onsen tamago (poached egg), and fish cake slices.

Kake Udon is all about simplicity, so we usually garnish the noodle soup with thinly sliced green onion and Shichimi Togarashi (Japanese seven spice). For variety, you can experiment with different toppings, and these ingredients are readily available at Japanese markets.

As you can see, the possibilities are endless. No matter how you prepare it, udon is bound to satisfy.

Toppings that do not require any prep:

Toppings that require additional prep:

Japanese bowls containing Classic Udon Noodle Soup called Kake Udon or Su Udon, topped with sliced green onion.

Kake Udon vs. Kamaage Udon

Lastly, I want to briefly discuss Kamaage Udon (釜揚げうどん), another type of udon noodle dish that resembles Kake Udon.

Many people get confused with both types of udon as they are served with minimal garnishes, despite being prepared differently.

Kamaage literally translates to “pull out of the pot,” and it has a unique serving style. Unlike most udon noodles, which are quickly rinsed under cold running water after cooking, Kamaage Udon is served directly from the pot into a bowl, often with the hot cooking liquid. Because the cooked noodles are never rinsed with cold water, Kamaage Udon has a distinct softer, velvety texture and starchy flavor. You would then dip the noodles into a dipping broth called ‘tsuyu (つゆ)’ served alongside.

So it is rather different from Kake Udon, where the noodles are chewy with a supple bite, and a dashi broth is poured into the bowl of noodles.

More Delicious Udon Recipes

Japanese bowls containing Classic Udon Noodle Soup called Kake Udon or Su Udon, topped with sliced green onion and shichimi togarashi (Japanese seven spice).

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Japanese bowls containing Classic Udon Noodle Soup called Kake Udon or Su Udon, topped with sliced green onion and shichimi togarashi (Japanese seven spice).

Udon Noodle Soup (Kake Udon)

4.67 from 92 votes
Classic Udon Noodle Soup (Kake Udon or Su Udon) is all about simplicity. Thick, chewy noodles and a delicate homemade broth deliver a hot bowl of comfort. Enjoy this vegan-adaptable soup as is or add tempura, fish cake, and vegetables for a more substantial meal.

Video

Prep Time: 5 minutes
Cook Time: 10 minutes
Total Time: 15 minutes
Servings: 2

Ingredients
 
 

For the Homemade Broth

For the Quick Broth (optional)

  • cup mentsuyu (concentrated noodle soup base) (or enough to make cups, 600 ml of soup; each brand is different, so follow your bottle‘s instructions for hot udon soup (うどん or めんのかけつゆ); I used Kikkoman Koidashi Hontsuyu; you can make my Homemade Mentsuyu)
  • 2⅓ cups water (for my bottle‘s mentsuyu-to-water ratio of 1 to 7; please adjust the water based on your bottle‘s dilution ratio for hot udon soup)
  • 1 Tbsp mirin

For the Udon Noodle Soup

  • 2 servings udon noodles (1.1 lb, 500 g frozen or parboiled udon noodles; 6.3 oz, 180 g dry udon noodles; or 10.6 oz, 300 g Homemade Udon Noodles)
  • toppings of your choice (thinly sliced green onion/scallion, shichimi togarashi (Japanese seven spice), and more options in the blog post)
Japanese Ingredient Substitution: If you want substitutes for Japanese condiments and ingredients, click here.

Instructions
 

To Prepare the Homemade Broth

  • In a medium saucepan, add 2⅓ cups dashi (Japanese soup stock), 1 Tbsp mirin, 1 tsp sugar, 1½ Tbsp soy sauce, and ⅛ tsp Diamond Crystal kosher salt.
    Udon Broth 1
  • Bring the broth to a gentle simmer. Once the broth is simmering, remove it from the heat. Cover with a lid and set aside.
    Udon Broth 2

To Prepare the Quick Broth (with mentsuyu; optional)

  • Follow the instructions on your concentrated mentsuyu bottle for the correct mentsuyu-to-water dilution ratio for noodle soup broth (shown here as めんのかけつゆ).
    Mentsuyu / Tsuyu (Japanese Noodle Soup Base) | Easy Japanese Recipes at JustOneCookbook.com
  • In a medium saucepan, combine the water, mentsuyu and mirin. For the brand of mentsuyu that I use, I add 2⅓ cups water, ⅓ cup mentsuyu (concentrated noodle soup base), and 1 Tbsp mirin. Bring it to a simmer over medium heat. Once simmering, remove the pot from the heat. Cover with a lid and set aside.
    Udon Noodle Soup with Mochi 1

To Cook the Udon Noodles

  • Bring a large pot of water to a boil. When the water comes to a full rolling boil, add 2 servings udon noodles and cook according to the package instructions. This brand of frozen udon noodles requires reheating them for 1 minute. Using chopsticks, stir the noodles to loosen them up. For fresh noodles, see the cooking instructions in my Homemade Udon Noodles recipe.
    Kake Udon 1
  • When the noodles are done cooking, drain them in a colander or pick them up with a fine-mesh strainer. Serve the hot udon noodles in individual bowls.
    Kake Udon 2

To Serve

To Store

  • You can keep the udon noodles and broth separately in airtight containers and store them in the refrigerator for up to 3 days.

Nutrition

Calories: 271 kcal · Carbohydrates: 54 g · Protein: 8 g · Fat: 1 g · Polyunsaturated Fat: 1 g · Sodium: 554 mg · Potassium: 41 mg · Fiber: 4 g · Sugar: 3 g · Vitamin A: 60 IU · Vitamin C: 1 mg · Calcium: 25 mg · Iron: 1 mg
Author: Namiko Hirasawa Chen
Course: Soup
Cuisine: Japanese
Keyword: udon noodle
©JustOneCookbook.com Content and photographs are copyright protected. Sharing of this recipe is both encouraged and appreciated. Copying and/or pasting full recipes to any website or social media is strictly prohibited. Please view my photo use policy here.
Did you make this recipe?If you made this recipe, snap a pic and hashtag it #justonecookbook! We love to see your creations on Instagram @justonecookbook!

Editor’s Note: This post was originally published on October 8, 2021. It was republished on May 3, 2024, with more helpful content, new images, and a new video.

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4.67 from 92 votes (87 ratings without comment)
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I made this and I’m not sure if it was the dashi that I used but it was very salty! I’m going to try again and dilute the broth with water or stock to see if that works. (The dashi bottle only has Japanese on it, so for all I know, it’s a concentrate. 🙈)

I can’t believe how perfect this simple recipe is! I appreciate this website so much! Every recipe comes out perfect! You are my absolute trusted go-to for every japanese, or japanese american recipe!5 stars

Hi Andrea! We are glad to hear you enjoyed Nami’s recipe!
Thank you so much for trying her recipes and for your kind feedback.

Hi,
Is the store bought Dashi broth vegetarian based or like beef/chicken bullion type?
Thank you.5 stars

I just made this and it’s very delicious. My broth was a bit too fishy so I added miso and it’s fantastic! Thank you for sharing these amazing recipes5 stars

Hi Pat! We are so happy to hear you enjoyed the dish!
Thank you for trying Nami’s recipes and for your kind feedback! Happy Cooking!

Is this just the same as bukkake udon or is this a completely different dish?

Hi Benson! Thank you for reading Nami’s post and trying her recipe!
The Bukkake Udon has more dark sauce and less liquid in the dish. You enjoy the texture of Udon with the sauce.
The Kake Udon is more like a noodle soup, and the soup broth is very flavorful that you can have it as soup.
There are two different dishes.
We hope this helps!🙂

I really loved this recipe! It was quick, simple, and delicious! I found it a bit too salty for my taste so I added a little extra sugar. Is it suppose to be fairly salty or is it because I used hondashi or maybe cooking mirin?5 stars

Hi Kris! Thank you very much for trying Nami’s recipe and for your kind feedback!
Yes. Hondashi and cooking mirin have salt in them, and it will make the dish saltier.😉

We have made your homemade udon noodles and are looking forward to making this soup. I am a little confused as to the amount of noodles to use. Your noodle recipe says 150g is one serving but the soup recipe for two servings says to use 500 g. Should we only be using 300 g of noodles for two servings?

Hi Celeste! Thank you very much for trying Nami’s recipes, and bringing this to our attention.
If you are using the homemade noodle, 300g is better. We had made the necessary changes to the recipe and made it more clear.😊

So tasty! I “made” the konbu dashi (it’s easy to impress people by saying you make a “cold brewed konbu stock”, when all you’re doing is putting some seaweed in water :D) and the udon noodles according to your recipes. It all turned out so well! Definitely going to pick up some shichimi, didn’t have any at hand so I went really lazy and just sprinkled a bit of cayenne pepper on top. Such a simple and refreshing soup!

Looking forward to trying some more of your udon recipes!

Hi Anderson! Thank you very much for trying Nami’s recipe and for your kind feedback!
We are so glad to hear you enjoyed Udon soup. Here is a link for more Udon recipes: https://www.justonecookbook.com/#search/q=udon
We hope you enjoy it! Happy Cooking!

5 stars! I made this with your homemade udon noodle recipe and enjoyed with some simmered daikon. I feel so comforted! I think your water and mentsuyu ratio is the wrong way around though 😉5 stars