Spray a large skillet with olive oil, and heat over medium heat.
Add in the sliced onions and bell peppers and cook for 10 minutes until softened and starting to caramelize.
Transfer the vegetables to a bowl, and add the sliced steak to the pan.
Sprinkle the steak with garlic salt and pepper and cook for 5-8 minutes until cooked through.
Meanwhile slice the hoagie rolls ¾ way through, and use your fingers to hollow out and remove ⅓ of the bread from the interior of the rolls (this removes calories, carbs, and gives you more room for the good stuff.)
Add the veggies back to the pan and toss well, then turn off the heat.
Divide the steak and veggies between each roll, and top immediately with provolone (so it melts).
Serve hot.
