Place beef in the freezer for 20-30 minutes to firm it up (this makes it easier to slice thinly).

Remove beef from freezer and slice against the grain into very thin slices, about ⅛-inch thick.

In a large bowl, combine soy sauce, brown sugar, sesame oil, minced garlic, grated ginger, grated Asian pear, rice wine, sesame seeds, half the green onions, and black pepper. Mix well until sugar is dissolved.

Add sliced beef to the marinade and mix thoroughly to ensure all pieces are coated. Cover and refrigerate for at least 1 hour, preferably 4 hours (overnight works great too for deeper flavor penetration).

When ready to cook, heat a large skillet or grill pan over high heat. Add the neutral oil.

Cook the marinated beef in batches to avoid overcrowding (which would steam rather than sear the meat). Each batch should take only 2-3 minutes until meat is caramelized and edges are slightly crispy.

Transfer cooked bulgogi to a serving plate and garnish with remaining green onions and extra sesame seeds.