Begin by marinating your ground beef or bulgogi beef in a mixing bowl. Combine soy sauce, brown sugar, minced garlic, grated ginger, and sesame oil. Ensure the beef is well-coated. Cover and let marinate in the refrigerator for at least 1 hour, or overnight for maximum flavor absorption.

Once marinated, form the beef mixture into equal-sized patties, slightly thicker in the center. Set aside on a platter while preheating the grill to medium-high heat (about 375°F to 400°F).

Place the shaped patties onto the preheated grill, cooking for about 5-6 minutes on each side, until a nice sear forms and the internal temperature reaches 160°F.

While the patties are grilling, place the burger buns, cut side down, on the cooler part of the grill. Toast for about 2-3 minutes until golden brown.

Assemble the burgers by placing a grilled patty on the bottom half of the toasted bun, layering kimchi, lettuce, tomato, and cheese. Add optional toppings as desired.

Serve hot with the top bun placed gently over the toppings, accompanied by sweet potato fries or a cucumber salad.