Heat a large pot on medium heat and sauté onion, garlic, and ginger until cooked through.
Add vegetable stock, spices, soy sauce, and vegetables. Meanwhile, drain and rinse the noodles. Pat dry and separate with your fingers as you add them to the pot.
Stir the mixture so all ingredients are evenly distributed. Bring the soup to a boil, then reduce the heat and simmer until all the vegetables are cooked through. Serve with additional chopped green onions and black pepper, if desired.