The stuffing is what puts this pork recipe over the top. It's delicious! Pair this with South Island Pinot Noir or Riverland Chardonnay.
For stuffing: In a medium saucepan, cook onion in hot butter over medium heat until tender. Remove from heat. Stir in dried pears, walnuts, cheese and vinegar.
Untie meat; trim fat from meat. Spoon stuffing onto the flat side of one portion of meat. Replace second portion of meat; retie with kitchen string. For rub: In a small bowl, stir together rosemary, the garlic, and pepper. Sprinkle mixture evenly over meat; rub with your fingers. For a charcoal grill, arrange medium coals around a drip pan in a grill with a cover. Test for medium-low heat above pan.
Cover and grill for 1 1/2 to 2 hours or until a meat thermometer inserted into center of meat registers 150F. (For a gas grill, preheat grill. Reduce heat to medium-low. Adjust for indirect cooking. Cover and grill as above, except place meat in a roasting pan.)
Remove meat from grill. Cover with foil & let stand for 15 minutes. (The meats internal temperature will rise 10F during standing. If desired, serve meat with grilled nectarine slices & garnish with rosemary springs.