Lightly freeze, to be able to easily cut into very thin slices, Flat Iron Steak (1 pound).
Combine the beef with Mirin (2 tablespoon), Soy Sauce (1 tablespoon) and Granulated Sugar (2 tablespoon). Marinate for 4 hours.
Meanwhile, heat Dashi Moto Soup Stock Base (4 cup) with Soy Sauce (1 tablespoon), Granulated Sugar (1 tablespoon) and Mirin (2 tablespoon). Bring to a simmer then remove from the heat.
In a separate pan, sauté 2 stalks of on the bias cut Scallion (2 stalk) in Peanut Oil (1 tablespoon) until they start to caramelize.
Add the beef and sauté over very high heat until the liquid has evaporated.
When the meat is nicely browned, remove from the heat.
Add the fresh-cooked Udon Noodles (to taste) to the broth, check and adjust your seasoning, – if necessary, add Togarashi Chili (to taste) for some extra heat.
Add the udon with the broth to a deep serving dish, top with the beef, sprinkle with Scallion (to taste).