Preheat a grill for cooking over medium-high heat.
Sprinkle the steak with a pinch each of salt and pepper, and grill until medium.
Preheat a 10-inch saute pan on the stove over medium heat and add olive oil, mushrooms, sliced garlic and finally onions. Saute until mushrooms and onions become soft, 2 to 3 minutes. Add Marsala, gravy, au jus, steak sauce, Worcestershire and oregano.
Slice the steak 1/2-inch-thick and add to the sauce. Add fresh basil and some salt and pepper and let simmer for 1 to 2 minutes, then finish with a squeeze of lemon. Serve with the feta, rice pilaf, grilled pita bread and a vegetable medley.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.