This simple seitan stir-fry is great choice for hearty appetites, and a warming dish for nippy evenings. Lots of red onion adds great flavor, and the mushrooms bolster the "meaty" quality of the seitan.
Heat the oil in a large skillet or stir-fry pan. Add the onions and sauté over medium heat until golden. Add the mushrooms, then cover and cook until they are done to your liking, about 5 to 7 minutes.
Stir in the seitan and soy sauce Turn the heat up to medium-high and stir-fry until the seitan chunks are touched by golden-brown spots.
Stir in the peas and stir fry for a minute or so longer. Season with pepper and serve.