In a medium bowl, combine the thinly sliced beef with soy sauce, brown sugar, gochujang, sesame oil, minced garlic, grated ginger, and black pepper. Mix well to ensure all beef slices are coated.

Cover the bowl and refrigerate for at least 30 minutes, or up to 2 hours, allowing the flavors to meld.

Preheat a grill pan or outdoor grill to medium-high heat. Lightly brush the grill grates with vegetable oil.

Place the marinated beef slices on the hot grill in a single layer, ensuring not to overcrowd the pan. Cook for 1-2 minutes per side, or until beautifully seared and cooked through to your desired doneness. Work in batches if necessary.

Remove the grilled beef from the pan and set aside on a cutting board to rest for a few minutes.

While the beef rests, in a small pot, whisk together gochujang, gochugaru, soy sauce, mayonnaise, brown sugar, minced garlic, and milk. Heat over medium-low heat, stirring constantly, until the sauce is smooth, slightly thickened, and simmering gently. Do not boil vigorously.

Remove from heat and set aside.

In a separate medium pot, bring 4 cups of water to a rolling boil. Add the instant ramen noodles (without the flavor packets).

Cook the noodles according to package directions, usually 2-3 minutes, until al dente. Reserve 1/4 cup of the ramen cooking water/broth, then drain the remaining water completely.

Add the reserved 1/4 cup of ramen broth to the creamy sauce and whisk well to combine. The sauce should be smooth and pourable.

Divide the cooked and drained ramen noodles between two serving bowls.

Pour the spicy creamy sauce evenly over the noodles in each bowl, tossing gently to coat the noodles.

Top each bowl of ramen generously with the sliced grilled beef.

Garnish with sliced green onions and toasted sesame seeds. If desired, add a soft-boiled or fried egg to each bowl and a drizzle of extra sesame oil.

Serve immediately and enjoy!