Wash the spinach and remove any tough stems. Bring 2 quarts of water to a biol, add the spinach, and cook 1 minute. Drain, squeeze out the excess moisture, and chop coarsely; reserve.
Bring 4 quarts of water to a boil.Stir in the noodles and cook until just tender, about 3 minutes. Drain, toss with sesame oil, and set aside. Combine the ingredients for the broth in a small saucepan and bring to a boil. Keep warm until ready to serve.