Make the Vegan Roast Beef: Preheat oven to 350F
In a large bowl, stir together the vital wheat gluten, nutritional yeast, onion powder, garlic powder, paprika, thyme, and black pepper.
In another bowl, whisk together the vegetable broth, olive oil, soy sauce, apple cider vinegar, and tomato paste.
Pour the wet ingredients in to the dry and knead the dough for a few minutes. It should be slippery but not dry. If it's too wet, add more vital wheat gluten tablespoon by tbsp.
Roll the seitan dough into a long log. Roughly 5 by 10. Wrap tightly in parchment paper and twist the sides and tuck them under the bottom of the loaf.
Place the wrapped loaf on a baking tray and bake for 90 minutes. Once done, it should feel firm. Refrigerate overnight.
Make the Gravy: Cut the seitan loaf in half. Put 1 half away and thinly slice the other half. Make these slices as thin as possible and don't worry about them all being the same length. Set aside.
Mince the onion. Place in large pan over medium heat with a pinch of salt. Cook onions until brown and caramelized, about 20-25 minutes. Add water as needed to prevent burning.
Once onions are caramelized, add minced garlic. Cook for another 2 minutes. Then, add the butter. When the butter is melted, add the flour and mix until no raw flour is visible. Next, add nutritional yeast and creole seasoning. Cook for another 1-2 minutes.
Add the no-beef broth, water, vegan worcestershire sauce, Louisiana hot sauce, and sugar to the pan and whisk until incorporated. Bring to a boil. Boil for 7 minutes.
After 7 minutes, reduce heat to a simmer and add thinly sliced vegan roast beef. Cook for an additional 7-10 minutes until gravy has thickened.
Assembly: Toast bread, if desired. Shred lettuce, slice tomatoes, and pickles.
Spread a good amount of vegan mayo on the bread and top with vegan roast beef, lettuce, tomato, and pickle slices. Serve & enjoy!