Check items off while grocery shopping - it’s remembered here.
Mix 1.5T soy sauce, 1T mirin, 1T sugar, 1/4t ginger, and 2T water to make the sauce.
Slice 1/4 onion about 1cm thick for a bit of bite.
Heat oil in a pan and sauté the onion from step 2.
Add the pre-prepared chuck beef and sauté. Once the beef looks cooked, add the sauce from step 1 and cook until the liquid reduces to a shallow simmer.
Over a little rice in a bowl, top with the beef and onion from step 4, chopped scallion, and an egg yolk.