1.Wash rice in a rice pot with a few changes of water. Add water to rice and set it to cook in the rice cooker. Thinly slice onion and cut green onion diagonally into thin slices. Set aside.
2.Place eggs into a pot of cold water. Set the heat to high until boiling. Once boiling set the stove to medium and boil for 6 minutes. Turn the heat off and place eggs in cold water. Once cool peel eggs carefully and set aside.
3.In a large frying pan (do not turn on the heat yet), add water, dashi granules, sake, mirin, soy sauce, and sugar. Stir to combine and dissolve the sugar.
4.Next, add the onion slices and spread them in the broth throughout the pan, separating the onion layers. Then, distribute the meat on top of the onions. Separate the thin slices of beef so the meat covers the onions.
5.Cover the pan with a lid. Now, turn on the heat to medium and start cooking. Once simmering, turn down the heat to simmer and cook, covered, for 3–4 minutes.
6.While simmering, open the lid and skim off the scum and fat from the broth twice with a fine-mesh skimmer. Sprinkle the green onions on top and cook covered for another minute.
7.Divide 2 servings cooked short-grain rice into large donburi bowls. Then, drizzle some of the pan sauce on top of the rice. Put the beef and onion mixture on top of the rice. If you’d like, drizzle additional remaining sauce on top. Enjoy!