Marinate the beef: In a large bowl, combine the soy sauce, brown sugar, honey, sesame oil, grated Asian pear, grated garlic, grated ginger, rice vinegar, green onions, black pepper, gochujang, and toasted sesame seeds. Add the thinly sliced ribeye and gently toss until evenly coated. Cover and refrigerate for 1–2 hours to allow the flavors to develop.
Prepare the creamy kimchi sauce: Add the mayonnaise, finely chopped kimchi, kimchi brine, gochujang, rice vinegar, honey, sesame oil, and grated garlic to an immersion blender cup, food processor, or blender. Blend until smooth and creamy. Cover and refrigerate until ready to serve.
Sear the bulgogi ribeye: Preheat a grill or cast iron skillet over high heat. Remove the beef from the marinade, allowing any excess marinade to drip off. Working in small batches to avoid overcrowding, sear the ribeye for approximately 60–90 seconds per side, until cooked through with lightly caramelized edges.
Assemble the bulgogi bowls: Divide the cooked white rice evenly among 3–4 serving bowls. Top each bowl with the seared bulgogi ribeye, sliced cucumber, optional kimchi, and green onions. Drizzle with the creamy kimchi sauce and finish with a sprinkle of toasted sesame seeds. Serve immediately.
Notes
For easier slicing: If you're slicing the ribeye yourself, briefly freeze it until firm but not frozen solid. This makes it much easier to cut thin, even slices against the grain.
Don't skip the marinating time: The marinade adds flavor and helps tenderize the beef. Refrigerate for the recommended time rather than cooking immediately.
Use high heat: A hot skillet or griddle helps the beef develop caramelized edges instead of steaming. Cook in small batches for the best results.
Drain excess marinade: Let the excess marinade drip off before adding the beef to the hot skillet. Too much liquid can prevent proper browning.
Adjust the spice level: Gochujang adds a little heat to both the beef and the kimchi sauce. For a milder version, reduce the gochujang in the sauce. For extra heat, add a little more to taste.
Make the sauce ahead: The creamy kimchi sauce can be prepared a day in advance and refrigerated in an airtight container. Give it a quick stir before serving.
Meal prep tip: Store the beef, rice, sauce, and fresh toppings separately. Reheat the beef and rice, then add the cold toppings and creamy kimchi sauce just before eating.