Heat 1 tablespoon of olive oil in a large skillet over medium heat. Add the sliced onions and bell peppers. Sauté until they are soft and slightly caramelized, about 8-10 minutes. Add minced garlic in the last minute of cooking. Transfer the cooked vegetables to a plate and keep warm.
In the same skillet, add the remaining tablespoon of olive oil. Increase the heat to medium-high. Add the thinly sliced sirloin, seasoning it with salt and pepper as it cooks. Sauté for about 5-7 minutes until the beef is browned and cooked through.
Return the sautéed onions and peppers to the skillet with the beef, mixing everything well.
Reduce heat to low and sprinkle the shredded provolone cheese over the beef and vegetable mixture. Cover the skillet for 2-3 minutes until the cheese is melted.
While the cheese is melting, lightly toast the hoagie rolls in an oven or on a skillet until golden brown.
Once the cheese is melted, scoop the beef mixture into each toasted hoagie roll. Add hot or sweet peppers if desired.
Serve immediately while hot, with optional sides like chips or a side salad.