- Cut the onions in half lengthwise, from top to bottom. Cut each half into ¼ inch slices and cutting lengthwise.
- Combine the onions, mirin, chicken, soy sauce, sake and dashi in a saucepan and place over high heat. When the liquid comes to a boil, reduce the heat and simmer for approximately 5 minutes, until chicken is cooked through. Mix the ingredients occasionally as they cook.
- To prepare the oyakodon one serving at a time, break 2 eggs into a bowl, and lightly beat the eggs. You want part of the yolk and whites to be lightly mixed, while the other parts are still separated.
- Transfer one fourth of the chicken mixture (about 1½ cups chicken, onions and broth) to a small skillet. Place the skillet over high heat. When the liquid comes to a boil, reduce the heat so the broth is simmering.
- Pour three-fourths of the egg mixture over the chicken, onions, and broth, Do not mix. Cook for about 1 minute, and then add the remaining one-fourth egg over the ingredients in the skillet. Cover the skillet and cook for 30 seconds more. Turn off the heat, and let the oyakodon rest, covered, for 1 minute.
- While the oyakodon is resting, scoop the cooked rice into a serving bowl. When the oyakodon is ready, uncover and slide the entire contents out of the skillet to rest over the rice. Tilt the skillet and use a spatula if necessary as the oyakodon should slide out easily. Garnish with nori, mitsuba and scallions. Add shichimi togarashi to accentuate the taste. Serve immediately and repeat this preparation for the remaining servings.