Combine the vegetable broth, dried shiitake mushrooms, kombu, and dried assorted mushrooms in a medium-sized pot. Bring to a simmer over medium-high heat, cover, and reduce to low. Simmer for at least 20 minutes to infuse the flavors of the mushrooms and seaweed.
While the broth is simmering, prepare the noodles and toppings in a separate pot. Cook the noodles according to the instructions - they should be just cooked and still quite chewy. They will continue to soften once served. When the noodles are ready, remove them from the water and set them aside.
If you are using the toppings suggested here, you can use the noodle-boiling water to blanch the fresh mushrooms and kale. The mushrooms will take 2-3 minutes (cook until tender) and the kale 1-2 minutes (cook until bright green).
Right before serving, remove the dried (now rehydrated) mushrooms and seaweed from the broth. You can either discard them or use them in a different dish. Stir the soy sauce, sesame oil, and black pepper into the broth.
Divide the noodles and broth between two large soup bowls. Top with mushrooms, kale, menma, and green onion. Serve immediately.
Notes
You may prefer to remove the ribs from the kale. They are tougher and more fibrous than the leaves.