01 - Preheat oven to 400°F (200°C).
02 - In a small bowl, combine the goat cheese, cream cheese (if using), chopped basil, chives, minced garlic, and lemon zest. Season lightly with salt and pepper, then mix until well blended.
03 - Using a sharp knife, carefully cut a pocket into the side of each chicken breast, taking care not to cut all the way through.
04 - Generously fill each pocket with the cheese mixture. Secure the openings with toothpicks if needed to keep the filling inside.
05 - Season the outside of each stuffed chicken breast with salt, pepper, and dried thyme (or herbes de Provence).
06 - Heat olive oil in a large ovenproof skillet over medium-high heat. Sear the chicken for 2 to 3 minutes per side until a golden crust forms.
07 - Transfer the skillet to the preheated oven and bake for 20 to 25 minutes, or until the chicken is cooked through and the juices run clear.
08 - Remove from the oven and let the chicken rest for a few minutes. Remove any toothpicks and serve hot.