Dice a small onion and sauté it in 2 tablespoons of oil for about 3-4 minutes.
Cut 2 cups of mushrooms into small pieces then add them to the onions and sprinkle with 1/2 teaspoon of salt. Sauté the mushrooms and onions for about 5 more minutes until tender.
Add 1 cup of water, 2 tablespoons soy sauce, 2 tablespoons tomato paste, 2 teaspoons paprika, 2 teaspoons liquid smoke, ½ tsp garlic powder, ½ tsp onion powder, and stir well.
Transfer the mixture to a blender or food processor and blend until it becomes a smooth paste.
Transfer the mixture to a glass bowl and add 1 cup of vital wheat gluten and mix well. Add another 1/2 cup of wheat gluten and mix again.
Add the final 1/4 cup of wheat gluten and knead it in with your hands until a firm dough forms and it no longer feels wet to the touch. (You may need to adjust it a little - the amount of wheat gluten needed may vary slightly depending on the amount of moisture in your onion and mushrooms.)
Flatten the gluten dough in a large circle on the countertop about 8 inches wide and 1 ½ inches thick.
Fry this large round of gluten dough in 2 tbsp of oil in a large frying pan for 3 minutes on each side. (This sears the gluten and stops it from expanding too much when you simmer it.)
Make the simmering broth
Make a broth by mixing 2 1/2 cups of water, 1 tablespoon soy sauce, 1 tablespoon tomato paste, 1 tablespoon maple syrup, 2 teaspoons liquid smoke, 1 teaspoon smoked paprika, 1/2 teaspoon garlic powder, and ½ teaspoon salt.
Simmer the ribs
Pour the broth over the seared gluten. Cover with a lid and simmer at a slow boil for 45 minutes. (Flip the gluten after 25 minutes) Check on it frequently towards the end of simmering to make sure all the liquid did not evaporate. If the liquid is low add a few more tablespoons of water.
Take the lid off and allow all the liquid to evaporate in the last few minutes of simmering or drain off any excess liquid before baking.
Bake the ribs
Add ½ cup of BBQ sauce to the bottom of a pie dish (or a small baking dish). Place the simmered gluten on top of the layer of BBQ sauce and then add another 1/2 cup of BBQ sauce to the top.
Bake at 350° F (176° C) for 30 minutes. You can also grill the ribs and brush them with the BBQ sauce while grilling.
Cut the seitan into long strips with a sharp knife about the size of ribs. (I find that a serrated knife works bests.) Brush with some additional BBQ sauce if desired and serve as you would ribs.
Notes
Wheat gluten is a very fine powder that can get messy. When pouring the flour into the bowl, hold it low in the bowl so it doesn't splash out or make a cloud of dust.
Gluten needs to be cooked, don't eat it raw. You know that it has cooked enough when it is firm and meat-like and no longer has a doughy texture.
You can cut the seitan in half or quarters before flipping it in the pan to make it easier to flip.
A square frying pan works great if you have one to make the ribs a more uniform shape, but it's not necessary.
If you still have a lot of liquid in the pan after 40 minutes of simmering, remove the lid and allow it to simmer uncovered for the last 5 minutes.
If your cooking liquid becomes low while simmering, add a few more tablespoons of water to the pan.