Cut the onions into thin wedges, the chicken into bite sized pieces, slice the shiitake and chop the mitsuba into 3 cm.
Combine the dashi stock, mirin, and soy sauce in a 7 : 5 : 2 ratio.
Onion: Pour 70-80 ml of the dashi seasonings in a pan, add onions, and heat over medium. Cook the onions first as they take longest to cook.
Chicken + Shiitake} Add chicken and shiitake after a minute of cooking. Let the chicken sit in the dashi sauce for about 15 minutes to tenderize the meat.
Beaten Egg #1: In another minute, pour the beaten egg (beat 10-15 times with chopsticks). Pour one whisked egg first to let it absorb the mixed soup base.
Beaten Egg #2: In another minute, pour in another beaten egg (whisked 10-15 times with chopsticks) and turn off the heat. ※ Add the egg that you want to make soft-set.
For an soft-set egg: Cover the pan and let it rest for 40 seconds.
Finish: Put it on a rice bowl. I recommend mitsuba and shichimi spice for toppings.
For the dashi seasoning: Combine the dashi stock (200 ml), mirin (150 ml), and soy sauce (50 ml) in a pot. Let it come to the boil.
Story Behind this Recipe
You could add other ingredients such as burdock root, carrot, green peas, mitsuba, or fresh shiitake mushrooms to bulk up the dish. You could replace the hon-mirin with a combination of 2 teaspoons of sugar and 5 teaspoons of dashi stock granules.
For the dashi stock, combine 3 cups of water (600 ml) and a little more than a teaspoon of dashi stock granules (4 g). You could leeks but I prefer onions because they absorb the dashi seasoning. Softening the chicken with hon-mirin would tenderize the meat more than mirin due to the high alcohol content. Hon-mirin would impart an umami flavor to the meat, but sugar gives it a simpler flavor. Cook in the order of the dashi stock seasoning, onions, chicken + shiitake mushrooms, egg (medium), and egg (medium).