I believe it's illegal to be from Philadelphia and not love cheesesteaks. Not above the law myself, I'm no exception to the rule. But since I'm halfway across the world I have to do with my own, which aren't too bad either. It's quick and easy. All you need are some quality ingredients and a craving for grease.
Melt a bit of butter in a pan and saute the onions. Sprinkle a little salt and pepper.
Slice a wedge in your roll so you're able to add more filling without breaking the bread into halves.
Season the beef with salt and pepper and place in the pan to brown. Once browned check seasoning and add the cheese on top. Fold the meat over and add more cheese.
Place in your roll and be sure to include that lovely dripping grease.
Notes: Traditionally the meat is chopped finely as you're cooking. Other traditional toppings include mushrooms, bell peppers, or pizza sauce.