Gyu don is a rice bowl topped with sliced beef and onion.
Ingredients
1 1/4 cups dashi
2 tbsp sake
3 tbsp mirin
1 tbsp sugar
1 onion, sliced thinly
7 oz sirloin beef, sliced thinly
3 tbsp soy sauce
3 eggs, lightly beaten (optional)
Method
Combine the dashi, sake, and mirin and boil. Add the sugar and stir until dissolved. Then add the onions and cook until tender. Add the beef and cook for 2 minutes, after which the soy sauce is added.
When the beef is cooked, pour the eggs if adding, to the meat and cook covered until the eggs are a bit runny but almost firm.
Serve on rice in a donburi (a larger sized rice bowl, usually made of lacquered wood, but also can be ceramic.)