In a large pot combine beef broth and water. Add kombu, dried shiitake, sliced ginger, and crushed garlic. Bring to a gentle simmer over medium heat — do not boil vigorously while kombu is in the pot.

Once small simmering bubbles appear (about 8–10 minutes), remove the kombu to avoid bitterness. Continue simmering with shiitake, ginger and garlic for 20 minutes to extract flavor.

After 20 minutes, add soy sauce, mirin, sake, brown sugar, sesame oil, salt and black pepper. Stir and simmer gently 5 more minutes. Taste and adjust seasoning — add up to 1 tsp more soy or 1/2 tsp salt if needed.

Strain broth through a fine mesh sieve into another pot or bowl to remove solids. Keep broth hot over low heat while preparing the rest.

Beef and Aromatics

Marinate beef: in a bowl combine the thinly sliced beef with 15 ml light soy, 10 ml sake and 1/2 tsp cornstarch. Toss briefly so slices are evenly coated; let sit 5–10 minutes while broth develops.

Heat a skillet or cast-iron pan over medium-high heat. Add 1 tsp neutral oil and when shimmering, add the beef in a single layer (work in batches if necessary). Sear quickly 20–40 seconds per side — the slices should brown but remain tender. Avoid overcooking.

When beef is nearly done, add 1/2 tsp sesame oil, toss once and remove from heat. Keep warm in a covered dish.

Noodles & Toppings

Soft-boiled eggs: if not already prepared, bring a small pot of water to a boil. Gently lower eggs and cook 6 minutes for jammy yolk (adjust 6–7 min to preference). Transfer to ice water for 5 minutes, peel, and cut in half. If using pre-marinated ajitsuke tamago, halve and reserve.

Cook noodles: bring a large pot of water to a rolling boil. Add ramen noodles and cook according to package directions (typically 2–4 minutes for fresh, 4–5 for dried) until just tender. Do not overcook. Reserve 120 ml of the noodle cooking water, then drain noodles quickly.

Briefly blanch vegetables: in the same boiling water, blanch napa cabbage and bean sprouts 20–30 seconds until bright and slightly tender-crisp. Drain and set aside.

Assemble bowls: divide cooked noodles between two bowls (approximately 110 g noodles per serving). Ladle hot strained broth over noodles (about 550 ml broth per bowl total divided; adjust to preference). Arrange sliced beef on top, add halved soft-boiled egg(s), blanched napa cabbage and bean sprouts, scallions, nori strips, pickled ginger if using, and sprinkle toasted sesame seeds. Drizzle chili oil if desired.

Final garnish and serve: serve immediately while hot. Encourage diners to mix egg yolk into broth for richness and to eat noodles and toppings together.