Preheat oven to 350°F.
Drain tofu and add to a food processor. (It's not necessary to press it first. The liquid is figured into the recipe.)
Add all remaining ingredients EXCEPT for the vital wheat gluten and purée until smooth. Scrape down the food processor as needed to ensure everything is evenly blended.
Add in vital wheat gluten and process until mixture comes together in mostly one mass, effectively cleaning the sides of the food processor. This can take a few minutes. If the mixture seems overly wet and is sticking to the sides of the processor, add in extra vital wheat gluten 2 tablespoons at a time until the right texture is achieved. It should be firm enough that it springs back quickly and does not hold an indentation when poked.
Shape the seitan into a log. Wrap it first with parchment and then tightly with aluminum foil, twisting the ends like a tootsie roll.
Bake in preheated oven for 1 hour, flipping the log over at the halfway point.
Allow seitan to cool for at least an hour before unwrapping. If you let it chill in the fridge fully, it will firm up and be easier to slice thinly for sandwiches.