Vegetarian Philly Cheese "Steak"

I became a vegetarian long before I ever saw Philadelphia, so I've never tasted one. I have seen them on TV plenty of times, though, and they always looked kind of tempting. Not so much the ones with fake cheese, but the ones that look like hearty sandwiches stacked with onions and peppers and cheese.
After the recent episode of "Top Chef" in which they attempted to make  a gourmet cheese steak, I decided to try and make a vegetarian version of the sandwich, using (once again) seitan for the "steak" part of it. I googled multiple recipes and finally mashed them all up together to come up with this version.

I make no claims for authenticity, but I found this delicious (though messy to eat!).

Normally I try to offer a gluten-free alternative to seitan, but in this case I admit that I'm not sure other veggie alternatives such as tofu or TVP chunks will do the job. If you do try this with them and it comes out well, please let me know. 

Philly Cheese "Steak" 

Ingredients (for 2 sandwiches): 

- 2  soft long rolls ("Hoagie" rolls or other soft large ones). 

- 1 package (8 oz/225 grams) seitan, ideally the kind that is already in strips

- 1 large onion

- 1 bell pepper (red/yellow/orange) 

- 1 jalapeno pepper (optional) 

- 1 tsp of canola oil + 2 tsp butter for the onions

- 2 tsp olive oil for the peppers

- 2-3 tsp of olive or canola oils for the seitan

- 2 cloves of garlic, minced

- Seasoning: salt, pepper, garlic powder, chili powder

- 2 slices of cheese: Swiss, American, Cheddar or your choice. 

- Ketchup (optional) 

Preparation: 

1. Prepare caramelized onions: slice the onion into thin strips. In a pan heat the olive oil with the butter until they are melted. Add the onions, and cook over medium-low heat, stirring occasionally, for about 30 minutes or until the onion is caramelized. This step takes some patience and care, because doing it over high heat will result in slightly charred onion as opposed to the soft sweetness of caramelized. You can go through the other steps while working on the onions.

2. Prepare the peppers: slice the bell pepper and jalapeno into thin strips. In another pan heat the olive oil and add the peppers, over medium-high heat. Cook, stirring, until the peppers are softer and have a bit of caramelization or browning at the edges.

3. Prepare the seitan: make sure that the seitan is cut into thin slices or strips. Heat the olive oil in a large pan. Add the minced garlic and cook for about a minute, until the garlic begins to turn golden. Add the seitan strips. Season well with salt, pepper and the other seasonings. Cook the seitan over medium-high heat, stirring not too frequently, to allow parts of the seitan to brown and turn a little crispy. 

4. Mix the seitan, onions and peppers together and cook for a few more minutes, tasting the seasoning to make sure you enjoy it. 

5. Slice the rolls most of the way through and open them up. Pile each roll high with half of the seitan and vegetable mix. Top the filling with a slice of cheese, and add ketchup if you like. Do your best to close the roll (it will be difficult, but that's half the fun), and make sure you have plenty of napkins when you eat this!