This recipe is part of our superfoods menu .
Note: Since miso and edamame have a lot of protein, the chicken can be omitted and this will be a nutritious vegetarian soup. The saltiness of miso varies per brand; choose a high-quality product to keep salt to a minimum.
Add 2 1/2 quarts water to pot. Increase heat, and bring to a boil. Add carrots, then reduce heat to simmer. Continue simmering until carrots are tender, about 10 minutes more. Meanwhile, bring a separate pot of water to a boil. Add buckwheat noodles, and cook until tender, about 3 minutes (do not cook in soup pot because they will soak up too much broth). Drain with a colander and run under cold water; set aside.
Coarsely chop reserved chard leaves, and add to soup along with edamame. Cook until just wilted, then quickly increase heat and bring liquid to a boil. Remove 1 cup boiling liquid, and swirl into a bowl with miso; set aside.
Add shredded chicken (if using) to pot; cook to heat through, about 2 minutes. Add noodles, and whisk miso mixture into soup. Serve immediately: Divide soup among bowls, and garnish with scallions.