Heat olive oil in saucepan. Add garlic and ginger and saute gently for one minute.
Add seitan and carrot, and saute until the seitan begins to brown.
Add mushrooms, water, sesame oil, soy sauce, and a dash of salt. Cover saucepan and bring to a boil. Turn the heat down low, leave the cover ajar, and cook slowly for 20-30 minutes, until the carrots are soft.
Stir the spinach into the broth. If desired, mix cornstarch with 2 teaspoons of cold water, and add to broth to thicken it. Cook uncovered for another minute until the spinach is cooked.