2 cups vital wheat gluten flour
2 cups water
Any flavoring you want
Mix the ingredients together and stir with a fork until the mixture comes together. The mixture will be very soft, but don't worry - it'll continue to firm up and you work with it. Knead well, and then cover the mixture with cold water and place in the refrigerator for at least an hour.
Remove the dough from the water and begin to knead it with your hands, over the bowl. You will notice that the water that comes out of the dough is cloudy. Occasionally dip the dough back in the water, refilling it often with fresh cold water, or run the dough under a slowly-running tap, until the moisture from the dough appears clear.
I tried three cooking methods: boiling in a broth, cooking in the oven in a foil-wrapped log, and cooking on a baking sheet uncovered. The last was the most successful.
Preheat your oven to 350 degrees and place the seitan on a well-oiled cookie sheet. Shape the dough until it appears roast-like, like a corned beef, and pop it into the oven. Cook for 15 minutes, flip, and cook for an additional 15-20 minutes.
If you wish you may douse the "roast" in sauce at this point, and cook until the sauce caramelizes and smells delicious. I served my "roast" with a quick dipping sauce of Sriracha, ketchup, hoisin and lemon juice, and ate way too much.