Osuimono is a refined Japanese clear soup built on fragrant homemade dashi made from kombu and katsuobushi, then delicately seasoned and finished with silken tofu, maitake mushrooms, and aromatic mitsuba. Its standout trait is the pure, umami-forward broth that showcases minimal, quality ingredients.
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Put the water and kombu into a pot and heat over very low heat. Remove the kombu just before it comes to a boil. A good guideline is when small bubbles appear around the inside edge of the pot. Add the katsuobushi and turn the heat to medium. When the katsuobushi rises gently to the surface, turn off the heat. Once the katsuobushi sinks to the bottom of the pot, strain through a fine strainer.
Break the maitake mushrooms into bite-sized pieces. Separate the mitsuba leaves and stems, and cut the stems into 3 cm (1.2 in.) lengths. Cut the tofu into 1 cm (0.4 in.) cubes. Put 300 ml (10.1 fl oz.) of the katsuobushi and kombu dashi made earlier into a pot and heat over medium. Once it comes to a boil, add the salt and Kikkoman Soy Sauce and mix. Add the maitake mushrooms and tofu, and simmer over low heat for 3 minutes. Place the tofu, maitake mushrooms, and mitsuba stems into bowls, then pour in the soup and top with the mitsuba leaves.
Store leftover dashi in an airtight container in the refrigerator for up to 3 days; do not store the assembled soup, as tofu and mitsuba will deteriorate. Reheat dashi gently and add fresh tofu, mushrooms, and herbs when serving.
fine strainer (essential for clear dashi) · small pot
Yes. Strain the cooled dashi and refrigerate in an airtight container for up to 3 days, or freeze for up to 1 month. Reheat gently before use.
Substitute with thinly sliced scallion greens or a small handful of fresh chervil or parsley for a lighter herb note, though the flavor will differ.
Silken tofu is traditional for its delicate texture; firm tofu will work but will be less refined. Avoid extra-firm, as it doesn't match the soup's delicate character.
Remove it just before a full boil—when small bubbles appear around the inside edge of the pot. This prevents the kombu from imparting a bitter, slimy flavor.
Yes. Keep the dashi ratio constant: 5g kombu and 10g katsuobushi per 500ml water. Scale all other ingredients proportionally based on the amount of dashi used.
