Submitted by Eric
Combine the vital wheat gluten with hot water in a bowl. Use just enough hot water to get all the gluten flour wet. Knead the mixture with your hands. It should form a big sticky mass. If it's not holding together well, that means your vital wheat gluten isn't fresh. That's not a major problem, it just means you have to knead longer. When the gluten is holding together fairly well, pour cold water into the bowl, and continue kneading. The water will turn whitish. Pour out the water when it is white, and get more cold water. Repeat this process for a while - you are washing the starch out of the vital wheat gluten, so that it becomes more protein-rich. Don't do it too many times, however, or the seitan will be too tough. Experiment with this a few times, and you will know when to stop rinsing. When you are satisfied with the results, it's time to cook the seitan.
To roast the seitan, first take the lump of gluten and put it into a baking/roasting pan. First sprinkle spices that you plan to use and soy sauce and oil on gluten and knead them into the gluten. Stretch out the gluten with your fingers so that it covers the whole bottom of the pan. This will help it cook faster and help flavor penetrate the seitan. Then pop it in the oven for 45 minutes at 425 degrees Fahrenheit. If you want to, you can cook it for the last 15 minutes in some sort of sauce (I usually use barbecue sauce) to increase the flavor once the seitan has acquired some firmness and texture.