In a large skillet, place oil, steak, garlic, and salt on medium heat; stir frequently until steak is browned.
Add peppers, onions, mushrooms and Worcestershire sauce; stir as vegetables soften; sprinkle with seasoned salt as you stir and toss.
Reduce heat to low and place cheese slices in a circle atop the meat/vegetable mixture.
Slice open the buns, if not sliced; remove some of the body of the bun to allow room for the sandwich filling; butter each interior side.
If able, lightly toast the buttered sides of the buns under a broiler or in a pizza/toaster oven.
Using a spoon or tongs, fill each roll.