Blanch spinach in boiling water for a few seconds. Drain water and immediately cool in water, then squeeze out water. Cut into sections 2" long. Cut Aburaage diagonally in half to make triangles. Cut Kamaboko into 1/2" thick slices. Cut the stems of Shiitake mushrooms and make decorative cuts on top if you like. Slice carrots into 1/2" rounds, cut with a flower cookie cutter, and blanch in boiling water for a couple of minutes. Chop green onion finely.
Warm Ichiban Dashi and season with Soy Sauce, Sake and Mirin. Keep it warm, covered, until used.
Cook dried Soba noodles according to the package.
Add Aburaage, Kamaboko, Shiitake and carrot flowers to the hot soup and cook for a minute. Then add Soba and let it simmer for a minute.
Divide noodles, toppings and soup into bowls, place spinach on top, and sprinkle on the chopped green onion. Add Shichimi if you like.