01 - Preheat your oven to 400°F (200°C). Line a baking dish with parchment paper or apply a light coating of cooking oil.
02 - Thoroughly pat the chicken breasts dry. Using a sharp knife, carefully create a horizontal pocket into the thickest portion of each breast, ensuring not to cut through to the other side.
03 - In a mixing bowl, combine the softened cream cheese, shredded mozzarella, grated Parmesan, chopped parsley, minced garlic, and optional chopped chives. Mix until all ingredients are thoroughly incorporated.
04 - Generously fill the pocket of each chicken breast with the prepared cheese mixture. If necessary, use toothpicks to secure the opening of the chicken breast.
05 - Brush the exterior of the stuffed chicken breasts with olive oil. Season both sides evenly with salt, black pepper, and paprika. Heat the remaining olive oil in a large skillet over medium-high heat and sear the chicken breasts for 2 to 3 minutes per side, until a golden-brown crust forms.
06 - Transfer the seared chicken breasts to the prepared baking dish. Bake in the preheated oven for 20 to 25 minutes, or until the chicken is fully cooked through and its juices run clear. The internal temperature should register 165°F (75°C).
07 - Remove the toothpicks from the chicken breasts. Allow the chicken to rest for 5 minutes before serving hot.