Heat the oil in a 3-quart saucepan over medium-high heat. Add the mushrooms and cook until lightly browned. Add the bok choy and crushed red pepper and cook until the bok choy is tender-crisp.
Stir in the broth and water and heat to a boil. Remove 1/2 cup hot broth to a medium bowl. Add the miso and stir until the miso is dissolved. Return the miso mixture to the saucepan. Reduce the heat to medium.
Add the zucchini and green onion and cook for 2 minutes or until the zucchini is tender. Season to taste with salt and pepper.
This nutritional information refers to each serving of the entire recipe and not just the products used as ingredients.