Heat a large nonstick skillet over medium-high heat. Sprinkle steaks with salt and pepper; coat with cooking spray. Add steaks to pan; cook 3 minutes on each side or until desired degree of doneness. Transfer steaks to a serving platter; keep warm.
Add mushrooms to pan. Coat mushrooms with cooking spray; sauté 3 minutes or until browned. Stir in wine, scraping pan to loosen browned bits. Cook until liquid almost evaporates. Remove pan from heat; add butter and rosemary, stirring until butter melts. Pour sauce over steaks.