Preheat grill or oven to 350°F.
Get your aluminum foil and tear off 8 strips, each about 10 inches long (roughly square). Stack the sheets to make 4 double-layer squares of aluminum foil. Pick up one stack and form it into a pocket using your fist. Repeat to make the remaining 3 pockets.
Portion equal amounts of shaved steak into each foil pack. Then add the onions, peppers and Italian dressing. Season to taste with salt and pepper and/or Italian seasoning.
Take two slices of Cooper Cheese and tear them into small pieces. Tuck the Cooper Cheese pieces into one of the foil packs, evenly distributing it within the steak, onions and peppers. Repeat for the remaining 3 foil packs.
Fold the edges of each foil pack together over the top to close it like a pouch. Press the foil together and fold it over to give your foil packs a good seal.
On the grill or in the oven, heat the cheesesteak foil packs, keeping them sealed, for 15 minutes, or until steak is done to your liking, veggies are tender and cheese is melted.
Serve with sliced Italian bread, spoon into your preferred hoagie bun or eat your cheesesteak straight out of the pouch!