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 (if using), salt, and black pepper. Mix thoroughly until all ingredients are evenly distributed and the mixture forms a cohesive filling.
03 - Using a sharp knife, slice a horizontal pocket into the side of each chicken breast, being careful not to cut all the way through. The pocket should be deep enough to hold a generous amount of filling while keeping the chicken intact.
04 - Fill each chicken breast pocket generously with the spinach and feta mixture. If the filling threatens to spill out, secure the opening with toothpicks by inserting them diagonally across the cut.
05 - Rub the outside of each stuffed chicken breast with olive oil, ensuring even coverage. Season generously with additional salt and pepper on all sides.
06 - Place the stuffed chicken breasts in the prepared baking dish, leaving some space between each piece to allow for even heat circulation.
07 - Bake for 25–30 minutes, or until the chicken is fully cooked. The internal temperature should reach 165°F when tested with a meat thermometer, and the juices should run clear when the chicken is pierced.
08 - Carefully remove any toothpicks from the chicken breasts. Serve immediately with fresh lemon wedges on the side for squeezing over the chicken.