Get a medium fire going. You can cook this on a charcoal grill, a BBQ, or on a grill plate over a campfire.

In a medium or large mixing bow, whisk together the maple syrup, olive oil, and rosemary. Set aside.

Wash your sweet potatoes, and slice into rounds that are about ¼" thick. Place in the mixing bowl, and gently toss to thoroughly coat the sweet potato slices.

Season with salt and pepper, to taste.

Lay 2 good sized pieces of heavy duty foil crosswise to each other, then spray generously with nonstick cooking spray.

Spread the coated sweet potatoes out in the center of the foil pieces, then fold to seal them in well. (See photos in the post, for how I do it.)

Cook - covered if possible - over your fire for about 10 minutes on each side.

Carefully open the packet to check for doneness - you want them soft, all the way through.

Season with additional salt and/or pepper if desired, and serve hot!