4 to 5 ounces of thinly sliced sweet onion
2 to 3 ounces thinly sliced fresh mushrooms
Sweet bell pepper slices, red and/or green (optional)
5 to 6 ounces of thinly sliced prime steak
2 slices provolone cheese
Vegetable oil, olive oil, or ghee for frying
Optional condiments: Worcestershire sauce, HP, Horseradish, hot peppers or whatever suits your fancy, or nothing but a little salt and pepper along the way.
Pre-heat the oven to 225F.
Heat about a tablespoon of oil or ghee in a saucepan over medium-high heat.
Once hot, add onions, mushrooms, and bell pepper slices if using.
Sprinkle in salt and pepper to taste.
Sauté until the onions and mushrooms begin to brown up, about 10 minutes.
Transfer pan contents to a heat proof bowl and hold in the pre-heated oven.
Add a couple more teaspoons of oil or ghee to the saucepan and allow it to heat up again over medium-high heat.
Once hot, add the steak slices and some salt and pepper.
Fry slices for about a minute or two per side, or until cooked through.
Transfer the meat to one side of a split bun, top with any additional condiments of choice and one slice of provolone cheese.
Remove the sautéed vegetables from the oven and spread them evenly on the opposite side of the split bun.
Top with the remaining slice of provolone cheese.
Put the sandwich on a baking pan and place it a couple of inches below the broiler.
Broil until the cheese just starts to brown.
Remove from oven and serve immediately.