preheat oven to 325 degrees
Place the gluten flour, yeast flakes, and the seasonings in a large mixing bowl, and stir them together. Mis the liquids in a measuring cup or small bowl. Pour this liquid into the dry ingredients, and mix them thoroughly. If there is still flour around the edges, add a small amount of additional water (1 or 2 tablespoons only!). You should now have a large, firm, spongy mass in the bowl.
Knead the gluten directly in the mixing bowl for about a minute, just to blend (do not add any more flour). Longer kneading will change the texture, and you may want to experiment with this later. Form the gluten into one smooth log, about 6 to 8 inches long. Wrap the log tightly in silver foil, twist the ends up so you have a tight package looking something like a big sausage. Place on a dry baking sheet. If you don't want the foil to be in contact with your food, wrap the gluten tightly in a piece of parchment paper before you wrap it in the foil.
Bake the "pastrami" for 1 1/2 hours. When done, unwrap the seitan, transfer it to a cooling rack, and let it cool thoroughly. When completely cool, wrap the seitan tightly in plastic wrap and chill in the fridge overnight or longer before eating. Slice into paper-thin rounds.