There is a technique when it comes to philly cheese steak making. I've been making them a long time and this works for all fillings.You can make it with packaged vegan deli slices (the picture on the box is not what you're looking for in a cheese steak - see above for a real cheezy steak)or home-made seitan; daiya cheddar or nooch sauce; vegenaise or tofu mayo, but at the end of the day, it's all about how you pull it all together. Here's my tried & true vegan cheese steak that never fails to cure my greasy meaty craving.
Start with a flat skillet and a little canola oil on medium heat. Add about 1/2 onion sliced in thin half moons.
Saute the onions until they are translucent, then shake on some oregano or italian seasoning.
Saute a little more until almost browned. Then spread the onion out around the pan and lay on 5-6 philly style deli slices (or thinly sliced seiatn.) Let brown a minute, then flip them over bringing most of the onions to the top as well. Then with 2 spatulas, rip the slices into bite sized pieces and heat through.
Pile the chopped faux meatiness into a strip down the middle of the pan and top with cheese (Tofutti American).
Toast a sub roll (or baguette or onion sub roll-yum) until just warmed, and spread on any condiments, I like vegenaise and ketchup and sometimes a little sriracha hot sauce on it. Then place the toasted roll over the pile in the pan.
Let sit a minute as the cheese melts to the bread.
Now here's how to get it out of the pan intact. Place a piece of foil over the roll and hold the foil and sandwich in place with one hand and using the other hand, flip the pan over so now you're holding the foil and the whole sandwich in your hand. It will be hot, so you may need a potholder over the foil if you've left it on the pan too long. Also have a plate ready to plunk the sandwich down on.
Slice in half and enjoy. If you like mushrooms and/or peppers on your steak add them when you saute the onions. You can also make a pizza steak, by spreading pizza sauce on the bread (toast it with the bread to warm) and using a mozzarella style cheese.