Udon Soup Recipe

Make dashi (if not using instant)

Place 6 cups cold water and a 4" strip of kombu in a medium pot. Let soak 20–30 minutes (or overnight in fridge) if you have time. Slowly heat over medium until just before simmering (small bubbles form). Remove kombu. Add 1½ cups loosely packed bonito flakes, bring to a gentle simmer for 30 seconds, then turn off heat and let flakes steep 1 minute. Strain through a fine-mesh sieve or cheesecloth into a clean pot, pressing gently to extract liquid. This yields roughly 6 cups dashi.

If using instant dashi granules, dissolve granules in 6 cups hot water according to package to yield 6 cups dashi.

Return the prepared dashi to medium heat. Add 3 tablespoons soy sauce, 2 tablespoons mirin, 1 tablespoon sake (if using), 1 teaspoon salt, and 1 teaspoon sugar (optional). Stir and bring to a gentle simmer. Taste and adjust: add more soy sauce for saltiness, more mirin/sugar for sweetness, or a pinch more salt. Keep broth hot on low while cooking noodles and toppings.

If using frozen or refrigerated udon: bring a separate large pot of water to a rolling boil. Add udon and cook according to package (typically 2–4 minutes for fresh/frozen). If using dried udon, follow package times (usually 8–10 minutes) until al dente. Stir occasionally to prevent sticking.

While noodles cook, prepare optional toppings: For soft-boiled eggs, bring a small pot of water to a simmer, gently lower eggs and cook 6–7 minutes for jammy yolk. Transfer to an ice bath for 5 minutes, peel and set aside. For tempura, prepare and fry per recipe or reheat prepared tempura until crisp. If using sliced chicken or tofu, warm or briefly sear in 1 teaspoon oil until heated through and browned slightly.

If using wakame, rehydrate 1–2 teaspoons in warm water for 5 minutes, drain and squeeze out excess water.

When udon are tender, drain in a colander and briefly rinse under warm water (especially if packaged fresh) to remove surface starch and prevent clumping. Divide noodles among serving bowls (about 6 oz per bowl for 2 servings).

Ladle hot broth over noodles (about 1½–2 cups broth per bowl). Arrange toppings: place sliced kamaboko or seared chicken/tofu, halved soft egg, wakame, sliced green onions, and tempura on top. Sprinkle toasted sesame seeds and a pinch of shichimi togarashi if desired.

If you like a hint of fresh ginger, grate a small amount (about 1 teaspoon) and add to each bowl or mix into the broth before ladling. Taste final bowls and adjust with extra soy sauce or salt if needed.

Serve immediately while hot. Provide extra condiments (soy sauce, chili oil, shichimi) at the table.