Trim the root of the komatsuna and make cross cuts. Wash the nameko mushrooms and drain them.

Boil water in a pot and add the komatsuna. Cook until tender, then remove and cool in water. Squeeze out excess water and cut into bite-sized pieces.

Add the nameko mushrooms to the same pot and boil for 1 minute. Cool in water and drain thoroughly.

In a bowl, combine the komatsuna, nameko mushrooms, and mentsuyu. Mix well.