1. Using a sharp knife, cut a pocket in each chicken breast by cutting horizontally through the thickest portion to, but not through, the opposite side. In a small bowl combine 1/4 cup of the feta cheese and the lemon peel. Spoon cheese mixture into each pocket. Sprinkle chicken with salt and pepper
2. In a large skillet heat oil over medium heat. Add chicken. Cook for 18 to 20 minutes or until chicken is no longer pink, turning once.