1
Lightly brush or spray the sweet potatoes, onion slices, and ginger on all sides with oil. Season with salt and pepper to taste. Grill over Direct Medium heat until the sweet potatoes, onions, and ginger are well marked, about 10 minutes, turning once. Finely chop the ginger. In a large saucepan, combine the sweet potatoes, onion, ginger, chicken stock, allspice, and cayenne. Bring to a boil, reduce heat, cover, and simmer for 30 minutes.