Marinate the beef: In a bowl, combine the soy sauce, brown sugar, sesame oil, rice vinegar, minced garlic, grated ginger, gochujang, sesame seeds, and black pepper. Add the thinly sliced beef to the marinade, mixing well to coat. Let it marinate for at least 20-30 minutes (or up to overnight for more flavor).

Prepare the corn: While the beef is marinating, heat a medium skillet over medium heat. Add the butter and corn kernels, cooking for 5-7 minutes, stirring occasionally until the corn is tender and slightly golden. Season with salt and pepper to taste. Optionally, sprinkle with chopped cilantro for added flavor and freshness. Remove from heat and set aside.

Make the creamy sauce: In a small bowl, whisk together the mayonnaise, soy sauce, rice vinegar, sesame oil, honey, garlic powder, and chili flakes (if using). Adjust the seasoning to your taste, adding more honey for sweetness or more chili flakes for heat. Set aside.

Cook the beef: Heat the vegetable oil in a large skillet or wok over medium-high heat. Once hot, add the marinated beef in a single layer, cooking for 3-5 minutes, stirring occasionally, until the beef is cooked through and slightly caramelized.

Assemble the bowls: To assemble, divide the cooked rice between bowls. Top with a generous serving of the Korean BBQ beef, then add a scoop of corn on the side. Drizzle with the creamy sauce and garnish with chopped green onions and extra sesame seeds, if desired.

Serve and enjoy: Serve immediately and enjoy the sweet, savory, and creamy flavors in every bite!