Caprese Chicken Foil Pack

Heat gas or charcoal grill. Cut 4 (18x12-inch) sheets of heavy-duty foil. Spray with cooking spray. Using sharp knife, cut 4 crosswise slits about 3/4-inch apart in top of each chicken breast, carefully cutting almost to bottom of chicken breast, but not through. Place each chicken breast on center of each foil sheet. Spoon slightly less than 1 teaspoon pesto into each slit in chicken breast. Place 1 mozzarella slice and 1/2 tomato slice in each slit. Sprinkle evenly with Italian seasoning, salt and pepper. Bring up 2 sides of foil so edges meet. Seal edges, making tight 1/2-inch fold; fold again, allowing space for heat circulation and expansion. Fold other sides to seal. Place packs on grill over medium heat. Cover grill; cook 10 minutes. Rotate packs 1/2 turn; cook 9 to 10 minutes longer or until juice of chicken is clear when center of thickest part is cut (at least 165 °F). Remove packs from grill. Carefully fold back foil; garnish with fresh basil leaf.