01 - Preheat 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 all ingredients are evenly distributed.
03 - Using a sharp knife, cut a horizontal pocket into the side of each chicken breast, being careful not to slice completely through. Open each pocket gently.
04 - Generously fill each pocket with the spinach-feta mixture. Secure openings with toothpicks to prevent filling from escaping during cooking.
05 - Rub the exterior of each stuffed chicken breast with olive oil. Season generously with additional salt and pepper on all sides.
06 - Place stuffed chicken breasts in the prepared baking dish, leaving space between pieces for even heat circulation.
07 - Bake for 25-30 minutes until chicken reaches internal temperature of 165°F and juices run clear when pierced.
08 - Remove toothpicks carefully. Serve immediately with fresh lemon wedges on the side for squeezing over chicken.