Brush the cooking grates clean. Grill the chicken, sage side down, over direct medium heat, with the lid closed, for 3 to 4 minutes. Using a metal spatula, gently turn the chicken over, taking care not to tear the prosciutto. Grill for 3 to 4 minutes more. To check for doneness, cut into the underside of one breast. The meat should be opaque all the way to the center. Remove from the grill and let rest for 3 to 5 minutes.
Brush the cooking grates clean. Grill the chicken, sage side down, over direct medium heat, with the lid closed, for 3 to 4 minutes. Using a metal spatula, gently turn the chicken over, taking care not to tear the prosciutto. Grill for 3 to 4 minutes more, until an instant-read thermometer inserted into the thickest part of the chicken registers 165°F. Remove from the grill and let rest for 3 to 5 minutes.
Brush the cooking grates clean. Grill the chicken, sage side down, over medium heat, with the lid closed, for 3 to 4 minutes. Using a metal spatula, gently turn the chicken over, taking care not to tear the prosciutto. Grill for 3 to 4 minutes more, until the thickest part of the chicken registers 165°F. Remove from the grill and let rest for 3 to 5 minutes.