In a skillet, heat olive oil over medium high heat.
Add thinly sliced steak and sprinkle salt. Cook the meat until cooked through, about 3 minutes.
Remove from heat and add grated provolone cheese.
Spread ½ tablespoon of mayo on one side of each bread slice.
Heat a skillet on medium high.
Place a slice of bread with mayo side down.
Layer one slice of American cheese, then ¼ of steak and cheese mixture, another slice of American cheese and top with second slice of bread with mayo side up.
Once the bottom bread is nicely browned, carefully flip the entire sandwich. (I used 2 spatulas to keep everything in place.)
Cook the sandwich until the cheese is melted and bread is nicely browned, pressing it with spatula to flatten the sandwich.
Continue with the remaining sandwiches. Serve immediately.