Gather all your ingredients.

In a mixing bowl, combine the soy sauce, brown sugar, sesame oil, rice vinegar, minced garlic, grated ginger, and black pepper. Whisk until the sugar is dissolved.

Stir in the chopped green onions and sesame seeds if using.

Prepare your beef cut, preferably short ribs or flank steak, and slice it against the grain.

Place the beef in a Ziploc bag or shallow dish and pour the marinade over it. Seal the bag or cover the dish and refrigerate for at least 30 minutes.

Preheat the grill to medium-high heat.

Remove the meat from the marinade and grill for about 5-7 minutes per side.

Let the meat rest for a few minutes before slicing.