In a medium saucepan or wok, add the onion, dashi, sake, soy sauce, and sugar. Bring to a simmer over medium heat.
120 g of onion, 120 ml of dashi, 60 ml of sake, 30 ml light soy sauce, 15 g of sugar, Salt
Cook, stirring occasionally, until the onion is softened, about 5 minutes.
Add the beef and cook over medium-high heat, stirring until the beef is cooked and the liquid is reduced by half, about 5 minutes.
250 g beef
Stir in the ginger and let simmer for 1 more minute. Adjust seasoning with salt and sugar to taste.
1 teaspoon of ginger
Divide the rice into bowls and top with the beef and sauce mixture. Garnish each bowl with a poached egg (if using), sliced green onions, beni-shoga, and togarashi. Serve immediately.
2 portions of cooked white rice, 2 Poached eggs, Green onions, Beni-shoga, Togarashi
Notes
The beef should be cut very thinly; freeze it before slicing for easier handling. Alternatively, ask the butcher