Heat a skillet or pan over medium-high heat. Add a bit of oil, then add the sliced onions and bell peppers. Sauté until they are softened and slightly caramelized.
Push the onions and peppers to the side of the pan and add the sliced steak. Cook the steak until it’s browned and cooked through, breaking it apart as it cooks. Add minced garlic and season with salt and pepper.
Remove the skillet from heat and stir in the shredded cheese until it’s melted and coats the steak mixture.
Lay out an egg roll wrapper in a diamond shape, with one corner facing you. Place a couple of tablespoons of the cheesesteak mixture in the center.
Fold the bottom corner over the filling, then fold in the sides to encase the filling. Moisten the top corner with a little water and roll it up, sealing the egg roll.
Heat the oil in a deep fryer or a large pot to around 350-375°F (175-190°C). Carefully add the egg rolls and fry until they are golden brown, about 3-5 minutes. Drain on paper towels.
Serve the Philly Cheesesteak Egg Rolls hot with your choice of dipping sauce, such as marinara or cheese sauce.