In a large glass bowl, mix together the vital wheat gluten, rosemary, thyme, sage, cumin seed, and garlic powder. In a separate bowl, combine the water and tamari or soy sauce. Using a sturdy spoon and working very quickly, gradually pour liquid into gluten mixture. The gluten will develop very fast and become very rubbery and elastic. If there is any remaining dry mix, quickly add a small amount of water to soak it up. Working on a flat, clean countertop, knead the dough a few times then shape into a log about the diameter of your fist. Shaping the dough can be a little tricky as it is rubbery and resistant, but just be patient. Set aside to rest for 15 minutes while making stock.
In a large stock pot, boil 8 cups water with 1/2 cup tamari or soy sauce, onion powder, and dashi kombu. Cut gluten log into desired shapes, maximum 1/2 inch thick. Individually drop the gluten pieces into boiling stock. Reduce heat to low, cover, and simmer for 45 minutes. Seitan may now be breaded and fried, chopped up and used in salads, or seasoned in any way you like.