1.Preheat The Oven'S Broiler, And Set The Oven Rack About 3 Inches From The Heat Source. 2.Trim Fat From Steak. Place Steak On Cold Broiler Pan; Broil For 5 Minutes. Turn, And Broil Until Desired Degree Of Doneness - 3 To 7 Additional Minutes For Rare, 8 To 10 Additional Minutes For Medium. 3.Make The Sauce While The Steak Is Cooking. Coat A Small Saucepan With Cooking Spray, And Add Mushrooms And Onion; Cook And Stir Until Tender. Stir In Marsala Wine, Water, Parsley, Beef Base, And Pepper. Simmer, Uncovered, Until Liquid Is Reduced To 3/4 Cup, About 4 Minutes. 4.Slice Steak, And Serve With Marsala Sauce.