Combine everything but the vital wheat gluten in a food processor. Blend that up into a paste, it should resemble hummus, taste for seasoning. Then add in the vital wheat gluten and blend and knead until you have a soft but sturdy dough. If your food processor has a hard time with it, you can split in half or smaller as needed and process in batches. If the seitan is too wet and sticky, add 1 Tbsp of vital wheat gluten at a time until it comes together. On the inverse, if it's too dry, add 1 Tbsp of water until it comes together as well.
Continue to knead the dough in the food processor until it's a firm but still slightly soft ball of dough (This should take about 5 minutes give or take). If it's in pieces it should be fine as long as you can mash it into a single ball. You should be able to stretch it out and see visible gluten strands. It should also not be too sticky. Slightly tacky is okay, but not sticky!
Form your Seitan into a ball, then let it rest for 20 – 30 minutes. If using an oven, preheat to 350 F / 176 C. Drizzle and rub a tablespoon or so of cooking oil on the seitan loaf, ensuring even coating. Next rub an even coating of the dry rub as well. Wrap the seitan in some Heavy Duty foil tightly. I recommend using two layers of foil. Place on a baking sheet, then bake for 1 hour or until the seitan is around 180 – 200 F internally (using a thermometer) flipping halfway through.Check NOTES for other cooking options! Let the Seitan cool to room temp, then rest in the fridge for 8 hours or OVERNIGHT. This is very important for the final texture to firm up. It will be too soft right out of the oven or instant pot.
The next day unwrap the roast, you can reuse the foil for another dish if you like. Add the roast to a parchment lined baking sheet and preheat the oven to 350 F.
Brush the glaze onto the roast and cover the top and sides completely. Don't worry about the bottom. Bake the roast in the preheated oven for 8 minutes. Then remove it, flip it onto the bottom, and now glaze the bottom (which is now the top!) and the sides. Bake again for another 8 minutes. Repeat this again, flipping and brushing the roast 2 more times in 8 minute intervals. So the total time will be 32 minutes. The seitan is ready to be carved and devoured!