For the Philly Cheesesteak
In a bowl, combine the melted butter, the garlic, the parsley and season with salt and pepper.
Split the roll in half crosswise and spread the mixture on the inside of each slice.
Lay the two slices of the roll on a baking dish covered with parchment paper and grill until golden.
Bring a saucepan to medium to high heat and add olive oil.
Add the beef, salt and pepper and cook both sides until browned.
Remove the beef from the saucepan and add some more olive oil.
Add the green and red peppers and the onion and cook until soft.
Restore the sautéed beef to the saucepan and stir.
Top with the two cheeses, without stirring, cover with a lid and cook briefly until the cheese melts.*
Lay the filling on the bread, close top and serve.
* Alternatively, lay the filling on the bottom side of the sandwich, top with the two cheeses and grill until the cheese melts.