1Combine beef with soy sauce, brown sugar, 1 tbsp sesame oil, 1 tbsp minced garlic, grated ginger, and mirin in a bowl. Marinate for at least 30 minutes, or up to 4 hours in the refrigerator.

2For the quick kimchi: In a separate bowl, combine shredded napa cabbage, julienned carrot, half of the sliced scallions, sliced radishes, 1 tbsp rice vinegar, the remaining 1 tsp sesame oil, a pinch of salt, and a pinch of sugar. Massage gently and let sit for 15 minutes.

3Prepare the gochujang aioli: Whisk together mayonnaise, gochujang, and remaining 1 tbsp rice vinegar until smooth. Set aside.

4Heat a large skillet or grill pan over medium-high heat. Add marinated beef in a single layer, working in batches if necessary, and cook for 2-3 minutes per side until caramelized and cooked through. Set aside.

5Lightly warm corn tortillas in a dry skillet over medium heat for 30 seconds per side, or microwave wrapped in a damp paper towel.

6To assemble: Spread a generous dollop of gochujang aioli on each warm tortilla. Layer with cooked bulgogi beef, a spoonful of quick kimchi, and a sprinkle of the remaining fresh scallions and toasted sesame seeds. Serve immediately.