Step 1: Prepare the Marinade - In a large mixing bowl, combine the balsamic dressing, olive oil, salt, and pepper. Whisk together until well combined.
Step 2: Marinate the Chicken - Add the halved chicken breasts to the bowl, ensuring they are well coated with the marinade. Cover and refrigerate for at least 30 minutes, or up to 2 hours.
Step 3: Preheat Your Skillet or Grill Pan - Heat a skillet or grill pan over medium-high heat and add a drizzle of olive oil.
Step 4: Cook the Chicken - Remove the chicken from the marinade and cook for about 6-7 minutes on each side, or until the internal temperature reaches 165°F (75°C).
Step 5: Add the Mozzarella - In the last few minutes of cooking, place slices of fresh mozzarella on top of the chicken and cover the pan to melt the cheese.
Step 6: Serve and Garnish - Remove the chicken from the heat, transfer to a serving platter, garnish with fresh basil leaves, and drizzle with any remaining balsamic dressing.