In a large resealable plastic bag, combine beef with garlic, pear, spring onions, soy sauce, sugar, sesame oil, rice wine, sesame seeds, fresh ginger and ground black pepper. Seal and refrigerate for 2 to 3 hours.
Heat a large frying pan over high heat. Spray with cooking oil and add beef. Cook, turning to brown evenly, for 3 to 6 minutes or until done.