Slice the onions thinly.
Rinse the rice well in water, then drain and add fresh water along with soy sauce, mirin, sake, and sugar. Mix everything together thoroughly.
Layer the ginger, sliced onions, and thinly cut beef in the rice cooker.
Cook using the normal setting on the rice cooker.
Once cooked, let it cool for about 10 minutes.
Serve the rice in a bowl and top it with the cooked beef.
If desired, garnish with a cooked egg, pickled ginger, and chopped scallions.
