Cook noodles according to package directions, omitting salt and fat. Drain; keep warm.
While noodles cook, heat a nonstick skillet over medium-high heat. Sprinkle both sides of steak with salt and pepper. Lightly coat steak with cooking spray. Add steak to pan; cook 4 minutes on each side or until desired degree of doneness. Transfer meat to a platter; keep warm.
Add port to pan, scraping to loosen browned bits. Stir in shallots and garlic; cook 45 seconds, stirring frequently. Add beef broth; bring to a boil. Cook 20 seconds; remove from heat. Add mustard and thyme, stirring with a whisk.
Cut steak diagonally across grain into thin slices. Serve steak and sauce with the pasta.