Optional ingredients: homemade tomato sauce, bell peppers, mushrooms, or your favorite cheese.
For the hoagies:
Preheat frying pan over medium-high heat. Cut the hoagie rolls horizontally to open up and make a pocket. Add the olive oil to the pan and stir in the onions. Put the steak on top of onions and add 1/2 ozs of the butter. Cover the pan for 21/2 minutes. The meat should have a cooked appearance on top and rare underneath. Using a fork and spatula separate steak from the onions. When the meat is cooked add the salt, remaining butter, and provolone. Cover to the pan to melt the cheese. Divide the steak mixture among the hoagie rolls and serve. If you like, you can add the optional ingredients to the steak mixture serving.