1.Boil, steam or microwave sweet potatoes until almost tender; drain.
2.Meanwhile, make sherry vinegar dressing by whisking together vinegar and oil in a small bowl. Season to taste.
3.Cook potatoes on heated oiled barbecue (or grill or grill pan) until browned and tender.
4.Place potatoes on serving platter. Drizzle with dressing; sprinkle with parsley and nuts.