In a mixing bowl, combine soy sauce, brown sugar, sesame oil, rice vinegar, garlic, ginger, and black pepper. Add the sliced beef and mix well. Let it marinate for at least 30 minutes.

Heat a skillet over medium-high heat. Add the marinated beef and cook for about 5-7 minutes until browned and cooked through.

In serving bowls, place a scoop of cooked rice. Top with the cooked beef, julienned carrots, sliced bell pepper, and chopped green onions. Sprinkle sesame seeds on top.