Mix all the spices in a pot (star anise, cloves, cardamom, cilantro seeds, and black peppercorn) and golden brown over medium-high heat for 1 or 2 minutes, stirring frequently.
Add the vegetable broth, water, onion, garlic, ginger, and seitan. Stir and simmer for about 20-30 minutes (I cooked it for 20 minutes).
Set aside, strain the broth and discard the spices and veggies. Keep the broth and seitan.
Pour the broth again into the pot and add brown sugar and tamari or soy sauce. Stir and set aside.
Cook the rice noodles according to package directions. Drain and rinse.
I like to serve Pho with some rice noodles, broth, seitan and some toppings like cilantro, basil, soybeans, and chopped chili pepper. You can also eat it plain or with onion, lime juice or even add Sriracha sauce.
Keep the leftovers separately in the fridge for 3-4 days.