Place the potatoes into a large pot with water to cover. Bring to a boil and cook over medium-high heat for about 10 minutes, or until tender.
Preheat the grill to medium-high heat. Drain potatoes and toss with olive oil, black pepper, rosemary and salt to taste.
Place the potatoes skin-side down over indirect heat on the grill and reserve liquid. Grill for about 15 minutes. Remove potatoes to a serving plate and sprinkle with the reserved olive oil mixture.
