In a soup pot over medium-high heat, bring water and dried mushrooms to a simmer. Let simmer while you prep other ingredients.
Preheat oven to 400F. Drain tofu, press between layers of paper towels to remove excess moisture, then cut into bite-size cubes. Line a sheet pan with parchment paper or Silpat, and arrange cubes in a single layer. Bake until the tofu begins to firm up and brown, about 20-30 minutes. Remove from oven and set aside.
Peel and dice onion. Cut broccoli crowns, carrots, and celery into bite-size pieces. Trim the ends off the bok choy, chop into small pieces, and rinse thoroughly in a colander under cool water to remove any dirt and grit. If your mushrooms are not pre-sliced, rinse gently and slice.
Add prepared vegetables to the soup pot along with soy sauce and ginger. Bring back up to a simmer, and let simmer until vegetables wilt down and become tender.
While soup simmers, cook ramen according to directions on package.
When vegetables are tender, reduce heat and stir in miso paste. Stir frequently until miso paste dissolves.
Serve soup with a handful of tofu cubes, and serving of ramen, and desired toppings. (HIGHLY recommend a heaping drizzle of tahini!)