Chop the onions.
Chop the peppers (optional).
Prepare the grill for two zone grilling, with coals on one side and nothing on the other.
Place a long sheet of Reynolds Wrap® Non-Stick Foil on the grill, dull side up (that's the non-stick side), with half of it over the coals.
Drizzle a tablespoon of olive oil on the foil.
Add the onions and optional peppers once the oil reads close to 300° F.
Season peppers and onions with salt and pepper.
Brown up the peppers and onions until slightly browned and soft.
Add the shaved beef and season with steak or beef rub.
Once the meat has browned, flip over to brown the other side.
After most of the meat is browned, form the meat/peppers/onions into a bun shape and top with two slices of cheese.
Slide the foil over to the side with no heat and fold the foil over and pinch off to form a pouch.
While the cheese melts, toast the buns by spraying the buns with oil.
Place the buns over the hot side of the grill to toast.
Once grill marks appear, rotate the buns 45 degrees.
Once they are cross hatched, remove from heat.
Open the foil pouch and slide the meat/peppers/onions/cheese onto the bun and serve.
Optional, wrap the assembled Philly Cheese Steak Sandwich in foil and place over the heat for a couple minutes to steam the bun.