Measure all of the dry ingredients (wheat gluten, flour, garlic powder, onion powder, herbs, and salt) into a large glass bowl and stir until well combined.
Stir in 1 cup of vegan broth with a silicone spatula, then knead with your hands until all of the flour is incorporated. (You may have to add a tablespoon or two of water to the dough to get all of the flour incorporated.)
When you have a firm, rubbery dough, bring 3 cups of broth and 3 cups of water to a boil. Rip off small walnut-sized pieces of dough and drop them into the hot broth. (They will double in size when cooked.)
Cover with a lid and turn the heat to low and simmer at a slow boil for 35 minutes. Then turn off the heat and allow it to cool for about 1/2 hour.
Transfer the cooked seitan, along with the broth, to a container with a lid and store in the fridge until ready to use. (You can use it immediately, but it will be firmer and more meat-like the next day.)
Cut up cooled seitan and toss it into any meal. Use as you would pre-cooked meat in any recipe.
Notes
The texture of the seitan will continue to firm up and become more meat-like if allowed to cool overnight in the fridge. However, you can use it after it simmers if you don't want to wait.
Use less salt and low-sodium broth for lower-sodium seitan.
Flavor VariationsChicken Seitan - Use poultry seasoning in the dough and not chick'n broth to mix the dough and simmer the seitan.Beef Seitan - Use oregano to season the dough, and not beef broth to mix into the dough and simmer the seitan. (You can also use vegetable broth with 1 teaspoon of soy sauce added for each cup of broth to make a beef-style broth.)