Prepare the beef by thinly slicing the beef into 1/4 inch strips, ensuring each piece is of equal thickness for even cooking. To enhance the flavor, season the beef with a light sprinkle of salt and sugar, allowing it to marinate in the refrigerator for at least 30 minutes.

In a large pot, sauté sliced onions until they become translucent. Next, bring homemade dashi to a boil in the same pot. Once bubbling, add soy sauce, dry sake, grated ginger, and a pinch of salt, allowing the flavors to meld together while simmering for 5 minutes.

Gently add the marinated beef into the broth and let it cook slowly for approximately 10 minutes until it becomes tender. This low and slow cooking method will infuse the beef with rich umami flavors from the broth.

To serve, place a generous cup of fluffy white rice in the center of a shallow bowl. Carefully ladle the flavorful beef and broth on top of the rice. Add one poached egg on top of the beef for added richness and texture. Finish off with sliced scallions adding a pop of color, and a sprinkle of togarashi for a touch of heat. For a tangy and spicy kick, serve with beni-shoga on the side.