Tentsuyu is tempura dipping sauce, and mentsuyu is noodle dipping sauce. Make tentsuyu in the microwave while you're frying the tempura. Make the dipping sauce for somen noodles this way, too! Add a little sugar to turn it into a sweet and savory sauce for your rice bowls. Turn the used bonito flakes into furikake rice sprinkles.
Measure the soy sauce, hon-mirin and water in a 200 ml capacity cup to fill it up to the 200 ml mark. Add a tons of bonito flakes and immerse them in the liquid. Microwave for 1 to 2 minutes, and the sauce is done.
The bonito flakes used in the sauce are delicious, so toast them in a frying pan until dried out. Add some bonito powder, chopped shio-konbu and toasted sesame seeds to turn it into furikake.
Story Behind this Recipe
My parents made dashi stock with lots of bonito flakes. They used to use freshly shaved bonito.
The ratio of water to soy sauce to mirin is 3:1:1, but this takes into acount that the sauce will be diluted a bit with grated daikon radish so it's quite salty. If you aren't using grated daikon radish use a 4:1:1 ratio instead. If you make a lot of the 3:1:1 ratio sauce, you can store it in the refrigerator for about a week. Chill this well to use as a dipping sauce for cold somen or soba noodles. Since somen noodles are cooled in ice water, this sauce should be just the right strength.