Easy Philly Cheesesteak

A. Preparing the ingredients

1. Thinly slice the beef against the grain to ensure tenderness.
2. Slice the onions and bell peppers (if using) into thin strips.

B. Cooking the filling

1. Heat olive oil in a skillet over medium-high heat.
2. Add the sliced onions and bell peppers to the skillet and sauté until they are soft and caramelized, about 5-7 minutes. Remove them from the skillet and set aside.
3. In the same skillet, add the thinly sliced beef and cook until it is browned and cooked through, about 3-4 minutes. Season with salt and pepper to taste.

IV. Assembling the sandwich

1. Preheat your oven to 350°F (175°C).
2. Slice the hoagie rolls in half lengthwise, without cutting all the way through.
3. Place a layer of cooked beef onto each hoagie roll.
4. Top the beef with a generous amount of sautéed onions and bell peppers.
5. Place slices of provolone or American cheese on top of the onions and bell peppers.
6. Wrap the assembled sandwiches in aluminum foil and place them in the preheated oven for about 5 minutes, or until the cheese is melted and the rolls are warm.