Beef Gyudon with Poached Egg

Boil dashi stock in a pot and add onion; cook for 3 to 4 minutes. Add soy sauce, sugar, and sake;
cook for another 3 to 4 minutes. Add grated ginger. Let sauce simmer and reduce for 10 minutes. Set aside.

Season beef with salt and pepper. Melt butter in a frying pan. Add beef; cook for 5 minutes.

Place 1 cup each steamed rice in 4 bowls. Divide beef among the bowls. Pour dashi sauce over beef and top with poached egg. Serve immediately.