Prep the Beef: Place the beef in the freezer for 20–30 minutes for easier slicing. Cut into very thin strips.
Make the Bulgogi Marinade: In a bowl, mix soy sauce, brown sugar, sesame oil, garlic, ginger, grated pear, green onions, black pepper, and sesame seeds. Stir well.
Marinate the Beef: Add sliced beef to the marinade, ensuring all pieces are well coated. Cover and refrigerate for at least 1 hour, preferably overnight.
Cook the Bulgogi: Heat a cast iron pan or grill over high heat. Add vegetable oil. Cook the beef in batches, searing quickly for 1–2 minutes per side. Avoid overcrowding the pan.
Serve & Enjoy: Garnish with additional sesame seeds and green onions. Serve over rice, in lettuce wraps, or with kimchi and ssamjang.