Heat olive oil in a large pot over medium heat. After 90 seconds, when the oil is hot, sauté torn pieces of seitan for 4-5 minutes until they are very lightly browned all over.
Add diced onion, celery, and carrots, and sauté, stirring occasionally, for another 4 minutes until vegetables are tender.
Add diced potatoes, minced garlic, dried thyme, and ground coriander. Cook for an additional 2 minutes until the garlic is fragrant.
Pour in vegetable stock or vegan chicken broth, and raise the heat to high until boiling.
After about 6 minutes boiling, when the potatoes are just barely fork tender, add noodles and cook until tender yet slightly firm. The exact timing will depend on how thick the noodles are.
Stir in chopped parsley, optional fresh dill, salt, and ground black pepper. Simmer for a few more minutes for the herbs to wilt and impart their flavor to the broth.
Serve hot, garnished with fresh parsley and dill, with freshly grilled sourdough bread on the side if desired.