Combine soy sauce, sugar, pepper, garlic, and sesame seeds in a bowl to create the marinade.

Thinly slice beef round roast into 1/4-inch thick pieces.

Place the beef slices in a resealable bag or container.

Pour the marinade over the beef, ensuring all slices are coated.

Marinate the beef in the refrigerator for at least 4 hours, or preferably overnight.

Preheat broiler.

Arrange the marinated beef slices on a broiling pan.

Broil until the beef is browned throughout, approximately 5-7 minutes per side.

Cook rice according to package instructions.

Wash and prepare lettuce leaves for serving.

Serve the bulgogi with cooked rice and lettuce leaves for wrapping.