01 - Preheat the oven to 400°F. Lightly grease a baking dish with cooking spray or a small amount of olive 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 all ingredients are well blended and the mixture holds together.
03 - Using a sharp knife, carefully slice a horizontal pocket into each chicken breast, cutting through the center without cutting all the way through to the other side. Open each pocket gently.
04 - Generously fill each pocket with the spinach and feta mixture, pressing lightly to pack the filling. Secure the openings with toothpicks to prevent filling from escaping during cooking.
05 - Rub the outside of each stuffed chicken breast with olive oil. Season generously with additional salt and black pepper on all sides.
06 - Place the stuffed chicken breasts in the prepared baking dish, spacing them evenly to ensure proper heat circulation.
07 - Bake for 25 to 30 minutes, or until the chicken is cooked through and the juices run clear when pierced with a fork. The internal temperature should reach 165°F.
08 - Carefully remove the toothpicks from each chicken breast. Transfer to serving plates and serve immediately with fresh lemon wedges on the side for squeezing over the chicken.