Creating delicious Korean BBQ Beef can be a seamless process if you follow these simple steps:

1. Slice the Beef: Start by slicing the flank steak or ribeye thinly against the grain. This ensures tenderness.
2. Prepare Marinade: In a bowl, combine soy sauce, brown sugar, sesame oil, minced garlic, minced ginger, rice vinegar, black pepper, and crushed red pepper flakes (if using).
3. Marinate: Place the sliced beef in a zip-top bag or a shallow dish. Pour the marinade over the beef, ensuring it’s well-coated. Seal and refrigerate for at least 30 minutes, or longer for better flavor.
4. Preheat Grill or Pan: Heat your grill or a large skillet over medium-high heat.
5. Cook the Beef: Remove the beef from the marinade, letting excess marinade drip off. Cook for 2-3 minutes on each side or until nicely browned and cooked through.
6. Garnish: Remove from heat and sprinkle with chopped green onions and sesame seeds.
7. Serve: Arrange the cooked beef on a serving platter alongside lettuce leaves and your choice of sides.

Following these steps will reward you with a stunning plate of Korean BBQ Beef that will delight everyone.