In a medium size stockpot, bring water to a boil. Add soup stock granules, soy sauce, mirin, sake and salt; continue to boil until granules are dissolved.
Add the vegetables and noodles; cook for 4-5 minutes or until noodles are tender. Add tofu; cook for another minute or two.
Transfer to soup bowls and garnish with chopped onions.
Serve and enjoy!
Recipe by Salu Salo Recipes at https://salu-salo.com/vegetable-udon-soup/