Philly steak sandwiches are made by caramelizing onions and bell peppers, grilling steak strips, seasoning with salt and pepper, combining the ingredients, melting cheese on top and scooping the contents into a hoagie roll. Variations can be made with added ingredients and different types of bread and cheese.
Lightly coat a skillet or griddle with oil, and heat at medium-high until the oil shimmers. Add one onion and one bell pepper, both thinly sliced, and salt and pepper to taste. Cook about five minutes, stirring occasionally, until the peppers soften and the onions caramelize. Move the mixture to the side of the skillet, and add thin slices of steak that have had the fat removed. Season the meat with salt and pepper. Cook, stirring occasionally, until the meat no longer appears red.
Combine the meat and vegetable mixture, and separate into piles roughly the size of your hoagie rolls. Place two slices of provolone cheese on top of each pile, and allow to melt slightly. Scoop each pile into a hoagie roll, and serve your Philly steak sandwiches.
As an alternative, add mushrooms to the vegetable mix. Bread types can also vary, but avoid anything too hard on the outside. For thicker breads, hollow out the inside to allow more room for the filling. American cheese serves as an option to provolone, while many prefer Cheese Whiz.