01 - Preheat the oven to 375°F. Lightly grease a baking dish with olive oil or nonstick spray.
02 - Pat the chicken breasts dry with paper towels. Using a sharp knife, cut a pocket lengthwise into each breast, being careful not to cut all the way through. Season the inside and outside generously with salt and pepper.
03 - In a small mixing bowl, combine the softened goat cheese, halved blackberries, diced jalapeño, chopped basil, and honey. Gently fold the mixture together until well combined.
04 - Spoon the blackberry-jalapeño filling evenly into each chicken breast pocket. Press gently to enclose the filling and secure the openings with toothpicks if needed.
05 - Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Sear the stuffed chicken breasts for about 2 minutes per side until a golden crust forms.
06 - Transfer the seared chicken breasts to the prepared baking dish. Top each breast with shredded mozzarella and drizzle with the remaining tablespoon of olive oil.
07 - Bake for 22 to 25 minutes, or until the chicken is cooked through (internal temperature reaches 165°F) and the cheese is bubbly and melted.
08 - Remove from the oven and let the chicken rest for 3 to 5 minutes. Carefully remove any toothpicks before serving. Garnish with additional fresh basil if desired and serve warm.