Wash and cut mushrooms into bite-sized pieces, then saute them in 1 tablespoon of cooking oil and sprinkle with 1/2 teaspoon of salt.
Heat over medium heat until they begin to release their juices, then add 2 tsp smoked paprika, 1/2 tsp onion powder, 1 tbsp Bragg's Liquid Aminos, 1 tsp liquid smoke, and 1/4 tsp black pepper and stir well.
Transfer the mixture to a food processor or blender, add 2 tbsp ketchup and 1/4 cup of water then blend for about 20 seconds. Slowly add the remaining 3/4 cup of water to the blended mushroom mixture until it's well combined.
Pour the blended mushroom broth into a large glass mixing bowl and set it aside while you prepare the TVP.
To rehydrate the TVP
In a small saucepan heat 1/3 cup of water, 1 tbsp of Bragg's Liquid Aminos, 1 tsp of liquid smoke, and 1 tsp smoked paprika. When it starts to boil, turn off the heat and add 1/2 cup of TVP. Stir well then let it sit and absorb the liquid for about 5 minutes.
Make the seitan burger patties
Pour the TVP into the mushroom broth and stir. Then add 1 cup of vital wheat gluten and stir well with a silicone spatula.
Add the remaining 1/2 cup of wheat gluten and knead it in with your hands.
Pull off a handful of dough and form it into a seitan patty and place it onto an oiled sheet pan.
Once all of the veggie burgers have been formed, put them in the oven a 375° F (190° C) for 35 minutes. (Take them out after 20 minutes to flip them.)
Notes
Don't over mix the gluten dough. Mix just enough to incorporate all of the vital wheat gluten with the broth and TVP.
Be sure that you cook your burgers long enough that the internal temperature gets to 160° F (71°C).
If your seitan burgers are doughy in the middle you need to cook them longer. They will have a meat-like texture when fully cooked.
*To make soy-free vegan burgers swap out the TVP step for 1 cup of cooked couscous.