1. Place chicken breast halves between 2 pieces of waxed paper.
2. Pound chicken to 1/8 thickness.
3. Mix sugar and cinnamon.
4. Coat apple slices with sugar mixture.
5. Divide apples among chicken breast halves; secure with toothpicks.
6. Cover and grill chicken 4 to 6 from medium coals, 20 to 25 minutes, turning after 10 minutes, until done.
7. Remove toothpicks.
8. Mix the apple cider and cornstarch in 1 quart saucepan.
9. Cook over medium heat until thickened and bubbly.
10. Spoon over chicken.