From Wiki:
"Steak is typically top round, although other types are often used. In one form of preparation, the steak is cut very thin so that it is almost translucent. The steak is placed on a lightly oiled griddle at medium temperature. The slices are quickly browned and then scrambled into smaller pieces with a flat spatula. Often, the steak is placed on top of already slightly fried onions to prevent the steak from becoming over-cooked. Thicker slices are also sometimes used (as are chunks of frozen thin slices which are defrosted as they are cooked).
Some locations with large volumes will griddle the steak in a large pile, chopping and flipping the steak with a large metal spatula until cooked to a light brown. The thicker pieces of steak, due to their need to be cooked more thoroughly, will be set in a single layer on the griddle and flipped until brown.
Cheese can be added at the last stage of griddling, placed on the bread before the meat is added, or ladled on top of the sandwich as the last step.
For adding cheese while griddling, the steak is shaped on the griddle so that the roll could cover it, the cheese is laid on top and allowed to melt for a minute, then the roll is placed over the steak and the spatula is used to scoop the entire contents into the roll.
In another method, the cheese is placed along the inner sides of the sliced roll and is either melted beforehand by a warmer or is melted by the heat of the freshly cooked steak. Lastly, pre-melted cheese or Cheez Whiz can be ladled on top of the sandwich.
The sandwich is served in a long roll, typically a 6-inch or 12-inch (15 or 30 cm) loaf of Italian bread (also known in Philly as a hoagie roll). The bread is sliced lengthwise to form a cradle, similar to a hot dog bun.
In the Philadelphia area, cheesesteaks are often made with rolls from Vilotti-Pisanelli or Amoroso's Baking Company.[3]) Locals believe there is something about "Schuylkill Punch", the nickname for Philadelphia's drinking water, that, by its alkalinity, makes the rolls distinctively flaky and airy.[citation needed]
A cheesesteak may include other optional ingredients such as griddled onions, sautéed green peppers, and mushrooms. Some menus include hot sauce, ketchup, or pizza sauce (a Pizza Steak, often with mozzarella as the cheese)."
It was so exciting that I can still remember the taste of the pizza. And there ain't no pizza around here 
