01 - Preheat the oven to 400°F. Lightly grease a baking dish with olive oil.
02 - Pat the chicken breasts dry. Carefully cut a horizontal pocket into the thickest side of each breast without slicing through completely.
03 - Season each chicken breast inside and out with salt and freshly ground black pepper.
04 - Spoon 1 tablespoon of basil pesto into each pocket, then layer slices of mozzarella and chopped sun-dried tomato inside.
05 - Secure openings with toothpicks if necessary. Place the stuffed breasts in the prepared baking dish.
06 - Drizzle the stuffed chicken with 1 tablespoon olive oil and sprinkle evenly with grated Parmesan cheese.
07 - Bake for 25 to 30 minutes until the internal temperature reaches 165°F and cheese is melted and bubbly.
08 - Remove toothpicks carefully, let the chicken rest for 5 minutes, then slice and serve.