Preheat oven to 425 degrees or use the broiler setting. Slice each roll horizontally through the middle.
Remove about 2/3 cups of the bread inside each roll. (See Notes) It allows the steak, onions, and mushrooms to fit perfectly inside.
Place 4 half slices of provolone on each roll, 2 on top and 2 on the bottom. This helps the sandwich from getting too soggy.
Place in the oven to melt the cheese. Carefully watch so they don’t burn! About 1-2 minutes, depending on your oven. Remove from oven and set aside.
Season the beef slices with garlic powder, pepper, and Perfect Pinch Steak Seasoning.
Heat a large frying pan on high heat. Add 1/2 tsp of oil and the beef. Cook for 1 minute, stir, and cook for 30 seconds. The cooked beef should be removed and set aside.
Add 1/2 tsp of oil and sliced onions. Sprinkle with 1/16 tsp of salt. Cook for 1 minute, stir, and cook for 30 seconds. Onions should be golden in color. Remove the onions and set aside with beef.
Lower the heat to medium and add 1/2 tsp of oil and sliced mushrooms. Sprinkle with 1/16 tsp of salt. Cook for 1 1/2 minutes, stir, cook another 1 1/2 minutes. Combine the onions, mushrooms, and steak and cook for 30 seconds.
Use half of the mixture for each sandwich. Place bread halves together and enjoy!