01 - Preheat oven to 375°F and lightly grease a baking dish with cooking spray or olive oil.
02 - Heat 1 tablespoon olive oil in a large skillet over medium heat. Add minced garlic and sauté for 30 seconds until fragrant. Add chopped spinach and cook, stirring constantly, until wilted approximately 2–3 minutes. Remove from heat and allow to cool slightly.
03 - In a mixing bowl, combine sautéed spinach, crumbled feta cheese, fresh dill, dried oregano, ground nutmeg, and lemon zest. Mix thoroughly until all ingredients are evenly distributed.
04 - Using a sharp knife, cut a horizontal pocket into each chicken breast, taking care not to slice completely through the meat. Work carefully to create a deep cavity for stuffing while maintaining the structural integrity of the breast.
05 - Season the interior and exterior of each chicken breast generously with salt and freshly ground black pepper, ensuring even coverage on all surfaces.
06 - Divide the spinach-feta mixture evenly among the four chicken breasts, filling each pocket completely. Secure the opening with toothpicks or kitchen twine to prevent the filling from escaping during cooking.
07 - Heat remaining 1 tablespoon olive oil in the skillet over medium-high heat. Place stuffed chicken breasts in the pan and sear for 2–3 minutes per side until a golden-brown crust forms.
08 - Transfer seared chicken breasts to the prepared baking dish. Bake for 20–25 minutes until the chicken is fully cooked through, reaching an internal temperature of 165°F when measured with a meat thermometer.
09 - Remove from oven and carefully remove all toothpicks or kitchen twine before serving. Allow chicken to rest for 5 minutes to redistribute juices.