Creating Beef Yakiniku is simple when you follow these easy steps:

1. Prepare the Marinade: In a bowl, combine soy sauce, mirin, sesame oil, sugar, garlic, and ginger. Mix well until the sugar dissolves.
2. Slice the Beef: Cut the beef against the grain into thin slices, about 1/4 inch thick for optimal tenderness.
3. Marinate the Beef: Place the sliced beef in a zip-top bag or bowl. Pour the marinade over the beef, ensuring all pieces are coated. Refrigerate for at least 30 minutes.
4. Prepare the Vegetables: While the beef marinates, wash and slice your chosen vegetables into bite-sized pieces.
5. Preheat the Grill: Heat a grill pan or an outdoor grill to medium-high heat. Lightly oil the grill grates to prevent sticking.
6. Grill the Beef: Remove the beef from the marinade, allowing excess liquid to drip off. Grill the beef slices for about 1-2 minutes per side, until they are cooked to your desired level of doneness.
7. Grill the Vegetables: After the beef is cooked, add the vegetables to the grill. Cook for about 3-5 minutes, stirring occasionally until tender and slightly charred.
8. Serve the Dish: Transfer the grilled beef and vegetables to a serving platter. Sprinkle sesame seeds and chopped green onions on top for garnish.
9. Enjoy with Rice: Serve the Beef Yakiniku hot alongside a bowl of cooked rice. You can also provide dipping sauces for added flavor.

These straightforward steps will guide you in creating an incredible Beef Yakiniku that everyone will love.