In a medium bowl, whisk together soy sauce, gochujang, sesame oil, brown sugar, minced garlic, and black pepper until well blended. Add your chosen beef, ensuring it's thoroughly coated in the marinade. Cover and refrigerate for at least 30 minutes, but overnight is preferable.

While the beef marinates, take a separate bowl and combine mayonnaise, sriracha, sesame oil, garlic powder, and a touch of brown sugar. Stir well until you achieve a smooth consistency.

In a large pot, pour in enough water to cover the ramen noodles and bring it to a gentle simmer over medium heat. Stir in gochugaru, soy sauce, rice vinegar, sesame oil, and a pinch of salt. Once bubbling lightly, add the ramen noodles and cook according to package instructions, about 3 minutes.

Heat a grill pan over medium-high heat until hot. Remove the beef from the marinade and sear it on the grill pan for 2–3 minutes per side or until you see a beautiful char.

Divide the cooked noodles between serving bowls, ladle the rich, flavorful broth on top, and generously drizzle the creamy sauce over the noodles. Top with sliced grilled beef and sprinkle with green onions and black sesame seeds.