Zaru Soba is a classic chilled Japanese noodle dish which features buckwheat noodles and a simple ice cold broth called mentsuyu or tsuyu. Mentsuyu is made from dashi, a kombu based stock, which is then mixed with soy sauce and mirin. If you already have dashi stock on hand, this Zaru Soba recipe can be made in about 5 minutes!
Prepare dashi stock. Bring water, kombu, and shiitake mushrooms up to a boil and simmer for 5 minutes. Turn off heat and add in bonito flakes. Steep for 30 minutes.
Strain and chill the dashi stock until ready to use. Mix 2 cups of chilled dashi stock with soy sauce and mirin. This will be enough for 2 servings.
Boil soba noodles according to package. Drain and rinse under cold water.
Prepare toppings. Grate daikon radish into a paste-like consistency. Squeeze out any excess liquid and form into a ball. Set aside along with the chopped green onions, wasabi, and shredded nori.
Place soba noodles on a bamboo mat (if you have one) or plate. Place grated daikon, chopped green onions, shredded nori and wasabi on a side dish. Serve dipping sauce in a separate bowl.
Add a preferred amount of shredded nori to the soba noodles and add the rest of the toppings to the dipping sauce.