To prepare Korean Chicken Breasts, follow these simple steps:

1. Prepare the Marinade: In a medium bowl, whisk together soy sauce, brown sugar, rice vinegar, sesame oil, minced garlic, grated ginger, gochujang, and black pepper until well combined.
2. Marinate the Chicken: Place the chicken breasts in a resealable plastic bag or a shallow dish. Pour the marinade over the chicken, ensuring it is fully coated. Seal the bag or cover the dish, then refrigerate for at least 30 minutes or up to 2 hours for maximum flavor.
3. Preheat the Cooking Surface: If grilling, preheat your grill to medium-high heat. If using a skillet, heat a tablespoon of vegetable oil over medium heat.
4. Cook the Chicken: Remove the chicken from the marinade, allowing any excess to drip off. Grill or sauté the chicken breasts for 5-7 minutes on each side, or until the internal temperature reaches 165°F (75°C).
5. Rest the Chicken: Once cooked, remove the chicken from the heat and let it rest for about 5 minutes. This allows the juices to redistribute, ensuring a moist chicken breast.
6. Slice and Garnish: Slice the chicken breasts into strips. Garnish with sliced green onions and sesame seeds for a beautiful presentation.
7. Serve Immediately: Serve the chicken hot, paired with rice, noodles, or steamed vegetables as desired.

These steps will guide you in creating Korean Chicken Breasts that are packed with flavor and sure to impress.