Instructions

1. Prepare a medium-hot charcoal fire in grill. Prick sweet potatoes all over with a fork. Wrap potatoes individually in a double layer of heavy-duty aluminum foil.
2. When charcoal briquettes are covered with gray ash and flames have subsided, spread briquettes into an even layer on bottom grate of grill.
3. Using long metal tongs, carefully place wrapped sweet potatoes on top of coals. Using a metal spatula, nestle coals around sweet potatoes; using tongs, place some coals on top of sweet potatoes. Grill, uncovered and undisturbed, for 20 minutes.
4. Flip sweet potatoes over. Nestle coals around sweet potatoes again, placing some coals on top of sweet potatoes using tongs. Grill, uncovered and undisturbed, until a paring knife or cake tester very easily pierces into middle of sweet potato, 20 to 25 minutes.
5. Remove potatoes from grill and let stand while you make the sauce.
6. Combine avocados, yogurt, lime zest and juice, chiles, garlic, cilantro, and parsley in a blender or food processor and process until blended and smooth. Transfer the sauce to a bowl and set aside.
7. Carefully remove the foil from potatoes. Remove potato skins and place potatoes on a platter, or cut potatoes in half lengthwise. Season with salt and pepper and top with the sauce.