2 Tablespoons olive oil 1 Tablespoon butter 1/2 pound shitake mushrooms, sliced 1 shallot, chopped 1 garlic clove, chopped 4-1/2" to 3/4" beef tenderloin steaks 4 prosciutto slices, trimmed to fit steaks 4 slices provolone cheese, trimmed to fit steaks 1/2 cup Marsala
Heat oil and butter in a large, heavy skillet over medium-high heat. When hot, add mushrooms, shallots and garlic and saute about 10 minutes. Season to taste with salt and pepper and set aside. Sprinkle steaks on both sides with salt and pepper. Add remaining Tablespoon of oil to skillet. Add steaks and cook until nicely browned on both sides. Remove skillet from heat and top each steak with a prosciutto slice, about a Tablespoon of the mushroom mixture and top with a slice of provolone. Cook just until cheese melts then transfer steaks to a plate and tent with foil. Add remaining mushroom mixture and Marsala to the skillet over medium-high heat and let boil until liquid is reduced by half about 3-5 minutes. Spoon sauce over steaks to serve.