1Cut pork diagonally into thin slices. Sprinkle pork with salt and pepper; rub with garlic. Spray 12-inch skillet with cooking spray; heat oil in skillet over medium-high heat. Add pork; cook 2 to 4 minutes, turning once, until no longer pink in center. Remove pork from skillet to platter; cover to keep warm.
2Respray skillet with cooking spray. Add mushrooms and shallots; cook 5 minutes, stirring often.
3Meanwhile, place cornstarch in small bowl. Gradually stir in broth and sherry with whisk until smooth. Stir broth mixture into mushroom mixture, scraping to loosen brown particles from bottom of skillet. Heat to boiling; cook 1 minute, stirring constantly, until thickened.
4Return pork and accumulated juices to pan; cook 1 to 2 minutes or until thoroughly heated.