Japanese Onion Soup

If you are interested in enjoying onion soup with a Japanese twist, be sure to try this Japanese Onion Soup recipe. You will love the harmony of onion flavor and traditional Japanese tastes.

Japanese Onion Soup is a simple dish made by adding onions to dashi broth and seasoning it with soy sauce. While onion soup is famous around the world for its French-style taste with bouillon and butter, in Japan, it is also enjoyed with dashi. The use of dashi gives the soup a light yet umami-rich flavor.

Dashi is a traditional Japanese broth typically made from ingredients such as kombu (dried kelp), bonito flakes (katsuobushi), dried anchovies, or shiitake mushrooms. Various types of dashi can be used for this soup, but I recommend using bonito dashi. The umami component in bonito dashi, inosinic acid, pairs well with the umami component in onions, glutamic acid, enhancing each other's flavors. This combination of umami components provides a rich and flavorful taste typically found in Japanese cuisine.

When using bonito dashi for this dish, there is one thing to keep in mind. If you prepare it using a regular method or use granulated dashi or dashi packs, the dashi flavor may become too strong, potentially overwhelming the delicate flavor of onions.

Therefore, when making this soup with bonito dashi, it is recommended to use ichiban dashi (first brew dashi) with a moderate amount of bonito flakes. This method allows you to extract the umami components from the bonito flakes while keeping their flavor delicate.

Ichiban dashi refers to a broth made by steeping bonito flakes in boiled water, rather than boiling them. You might find the term unfamiliar and the process complicated, but rest assured, it is quite simple.

The recipe includes instructions for making ichiban dashi, but for more detailed information, please refer to the page on 'How to make bonito dashi.'

In Japan, when we mention "Japanese onion soup," it refers to a dish similar to this recipe. However, if you are simply looking for a Japanese soup with onions as an ingredient, I recommend miso soup or suimono (a Japanese clear soup where the ingredients take center stage).

Both are traditional Japanese soups that can incorporate onions, so if you are curious, I suggest trying them as well.

Ingredients

---

---

Instructions

🕒 Total: 15 mins mins

If you already have bonito dashi (ichiban dashi) or another type of dashi, start from step 3. In that case, use 1 ⅔ cups (400 ml) of your dashi for 2 servings.

Step 1
Put water in a pot and bring it to a boil. Once boiling, turn off the heat and add bonito flakes. Let it steep for 2 minutes.

---

Step 2
Strain the mixture through a sieve lined with paper towels or a cloth (such as cheesecloth). Alternatively, if you don't mind some fine bonito flakes remaining, you can simply use a fine-mesh strainer. Bonito dashi (ichiban dashi) is now ready.

---

Step 3
Slice onion into bite-sized pieces. Thinly slice green onion.

---

Step 4
Return the dashi to the pot and bring it to a boil. Once boiling, add the onion slices and simmer them over low heat for 5 minutes. Then, turn off the heat, add salt and soy sauce, and let the flavors blend.

---

Step 5
Serve in each bowl and top with the green onions.

---

To store

You can store it in the refrigerator for up to 2 days.