Heat coals or electric grill, then place the chicken halves on wax paper.
In another container, combine sugar and cinnamon powder, mix, and then coat into the apple slices. Separate chicken and fold with the coated apple slices. Secure chicken and apples with a toothpick.
Cover and grill chicken from medium heat for about 25 minutes. Turn both sides to check if it reaches the desired consistency.
Mix apple cider and cornstarch in a saucepan over medium heat until it thickens. Stir constantly until it is bubbly. Spoon at the top of grilled chicken. Plate and serve.