Make the kombu base: put cold Water and Dried Kombu in a pot and let it steep for 20–30 minutes; then slowly heat until just before boiling, remove the Dried Kombu (do not boil).
Finish the broth: dissolve a small amount of Dashi into the warm liquid, then season gently with Mirin, Soy Sauce, and a pinch of Sugar and Rice Vinegar; keep it at a bare simmer on the stove or portable burner.
Prepare the proteins and vegetables: thinly slice the Beef Ribeye if not pre-sliced and arrange on a chilled platter; core and chop the Napa Cabbage into bite-sized pieces, trim and wash the Shungiku, slice the Leek on the diagonal, remove stems from the Shiitake Mushrooms and slice caps, trim the roots from the Enoki Mushrooms and separate clusters, peel and thinly slice the Carrot, and cut the Firm Tofu into cubes.
Cook or warm noodles/rice: prepare the Udon Noodles according to package instructions and set aside, and warm some Steamed White Rice if you plan to finish the broth with rice.
Assemble dipping condiments: put Ponzu Sauce in a small bowl and offer separate bowls of Grated Daikon, freshly grated Fresh Ginger, chopped Scallions, torn Shiso leaves, and a sprinkle of Toasted White Sesame Seeds so diners can customize their dips.
Bring the pot to the table and keep the broth at a gentle simmer so it stays clear and hot but not boiling.
To eat: swish a slice of Beef Ribeye through the simmering broth for just a few seconds until it turns pale pink (adjust time for desired doneness), then dip into Ponzu Sauce with grated condiments and sesame.
Cook vegetables and tofu in the same pot: add heartier items first (carrot, Napa Cabbage, Shiitake Mushrooms, Leek), then softer items like Firm Tofu, Enoki Mushrooms, and Shungiku so everything finishes tender but not mushy.
When you’re ready for noodles, add the cooked Udon Noodles to the pot to warm and soak up the broth, or scoop hot broth over Steamed White Rice to make a comforting bowl and top with Scallions and Shiso.
Taste and adjust: if the broth becomes too concentrated, add a little more Water and a splash of Mirin or Soy Sauce to balance; sprinkle additional Toasted White Sesame Seeds on dips as desired.
