Whisk vital wheat gluten, chickpea flour, 3 tbsp nutritional yeast, 2 tsp onion powder and 1 tsp garlic powder together in a bowl and set aside. Combine warm water (hot from the tap) with soy sauce, 1 tbsp nutritional yeast, 1/2 tsp vegemite (or marmite or vegan Worcestershire sauce), 1/4 tsp garlic powder and 1/4 tsp onion powder together. Pour liquid into flour mixture and stir to form a dough. If it's too dry, add another tbsp or two of warm water but becareful not to make it too wet or soggy. You want it to be firm, but pliable and moist. Knead 5-10 times then place into a large pot.
Pour beer over top (I left mine out for a few minutes, but it was still rather cool), cover and bring to a boil. Once boiling, add 1/2 tsp more vegemite, reduce to low and simmer until most of the liquid has absorbed, about 45 minutes to 1 hour. About 1/4 cup cooking liquid should line the bottom of the pot.
Use a butter knife (not a sharp knife) to shred thin slices off of the seitan. If the seitan is too wet or juicy for you, place slices on a cookie sheet and bake at 350F for 8-10 minutes on each side. Be careful not to over bake the seitan -- you want it slightly firmer but not dried out and hard. (see blog post for photo tutorial).
For "carnitas" slap seitan into whole wheat tortillas with lettuce and tomatoes, and spoon residual cooking liquid over the filling.