In a wok or skillet, heat oil over medium-high heat. Add beef strips 1/3 at a time. Stir-fry for 3 minutes or until browned, removing the done pieces to a plate lined with paper towels.
Return all the beef to the wok. Stir in orange peel, garlic, and ginger; stir-fry 1 minute.
In a medium bowl, combine cornstarch, broth, soy sauce, sherry, marmalade, and red pepper. Pour this mixture into the beef, stirring constantly. Bring to a boil over medium heat and cook for 1 minute. Serve hot.
