Cook noodles according to package directions. Drain and set aside.
Heat 1 tbsp oil in a large skillet over medium-high heat. Cook seitan until browned on all sides, approximately 5 to 6 minutes. Sprinkle with salt and pepper. Removed seitan from skillet, set aside.
Return skillet to medium-high heat, add butter. Cook onions for 1 to 2 minutes, then add mushrooms. Cook mushrooms until golden brown, approximately 8 minutes. Season well with salt and pepper.
Sprinkle flour over onions and mushrooms, stir and cook for 1 minute.
Slowly add broth, stirring continuously until a low boil achieved. Then stir in worcestershire, dijon mustard and sour cream until well mixed and creamy.
Return seitan to skillet. Bring to boil, then reduce heat to medium-low. Continue to cook for 3 to 4 minutes. Adjust seasonings salt to taste.
Stir in noodles, and cook until heated through. Sprinkled with chives/parsley (optional).