The Philly sandwich is often called the Philly cheesesteak or just a philly, and the recipe was originated by Pat’s King of Steaks in 1930. Pat Olivieri initially simply called the sandwich a steak sandwich and early versions did not, surprisingly, contain cheese as a main ingredient. The Philly sandwich known as the cheesesteak would come much later in the 1950s, when the processed cheese, Cheez Whiz® was added as topping, and you can still get steak sandwiches “widdout” (without) cheese if you so choose, at Pat’s or its nearby competitor Geno’s, and in a variety of other Philadelphia delis and restaurants.
The basics of the philly, as it was first made, were quickly cooked, very thin pieces of steak combined with fried onions. These were placed onto a long soft hoagie roll, with some of the roll scooped out. When processed cheese was added, the Cheez Whiz® would be spread on one side of the bread before the steak and onions were scooped on. Many people like to add other types of cheese to a philly sandwich, and cheeses like provolone or American cheese can be melted on the bread or directly atop the cooking steak.
You can add a great deal of variety to the Philly sandwich. Pizza steaks exist, which are ladled with pizza sauce and mozzarella. Other typical additions include grilled green peppers and mushrooms, together or separately. Philly sandwich lovers may spice up their steaks by adding hot sauce, or some prefer a little ketchup, though the these sandwiches can certainly be eaten without condiments too.
For residents or former residents of Philadelphia, there is nothing like the Philly sandwich, and some contend that Philly tap water provides some of the flavoring and excellence of most high quality rolls used. This would make it difficult to get an authentic Philly sandwich outside of Philly, though many restaurants outside of Philadelphia, and across much of the US, certainly do try to present steak sandwiches and even cheesesteaks in an authentic way. Those who grew up with the original Philly sandwich styles in Philadelphia may judge these harshly, but those who grew up outside Philly often find these imitations elsewhere to be quite delicious.