In a medium glass bowl, microwave the sweet potato slices for about 3–5 minutes until crisp tender.
Add the apple slices to the sweet potatoes (do not cook).
Mix the oil, salt, nutmeg and cinnamon and pour it over the apples and sweet potatoes. Mix to coat.
Place the apple-sweet potato mixture in a vegetable basket and grill over medium (indirect) heat for about 15–20 minutes until the apples and sweet potatoes are starting to brown.
Turn the potatoes and apples over every five minutes to make sure they cook evenly.