01 - Preheat the oven to 400°F. Lightly grease a baking dish with cooking spray or a small amount of oil.
02 - In a mixing bowl, combine crumbled feta cheese, chopped spinach, minced garlic, cream cheese, fresh dill, salt, and black pepper. Mix thoroughly until well blended and evenly distributed.
03 - Using a sharp knife, slice a horizontal pocket into each chicken breast, cutting carefully to avoid penetrating through the opposite side. Leave about 1/4 inch border around the edges.
04 - Generously fill each pocket with the spinach-feta mixture. Secure the opening with toothpicks to prevent filling from escaping during cooking.
05 - Rub the exterior of each stuffed breast with olive oil. Season generously with additional salt and freshly ground black pepper on all sides.
06 - Place the stuffed chicken breasts in the prepared baking dish, spacing them evenly to allow proper heat circulation.
07 - Bake for 25-30 minutes until the chicken reaches an internal temperature of 165°F and the juices run clear when pierced with a fork.
08 - Carefully remove toothpicks before serving. Plate the chicken breasts with fresh lemon wedges on the side for squeezing over the finished dish.