Combine all the wet ingredients into a food processor. Blend until nice and smooth.
In a large bowl, place the Vital Wheat Gluten. Pour in the wet ingredients and start to mix. Once the seitan has started to come together, remove from the bowl. Your mixture should be firm, but fliable. You can add a more Vital Wheat Gluten or water depending on the consistency of your seitan.
THIS IS IMPORTANT. Start to kneed the seitan by hand. You have to work the seitan for at least 5 minutes. The more you kneed it, the firmer the texture on your "chicken". Keep kneeding, pounding and working the seitan. The seitan will firm up the more you kneed it.
In a large pot, add the 8 cups broth, rosemary, thyme and onions. Bring to a boil
Cut the seitan into smaller pieces. The seitan will expand quite a lot during to cooking stage in the broth. I use a roller and roll out each piece to about the size of a hamburger bun. These pieces should be thinner than you want them for your chicken sandwich due to the expansion of size. If you want chicken tenders, you can leave your pieces a bit larger and tear them into size once they are cooked.
Add you seitan pieces to the broth, reduce the broth to a low simmer and cook for 60 minutes.
Remove and dry off the seitan. Place in the refrigerator and let cool. Since this recipe makes quite a lot of seitan, I usually freeze some for later. I typically don't leave it in the freezer for more than 1 month, but I read you can leave up to 3 months.