1. Preheat grill to medium-high heat (350° to 400°). Microwave potatoes in a microwave-safe bowl at HIGH 5 to 7 minutes or until almost tender.
2. Combine butter and remaining ingredients in a small bowl. Brush cut sides of potatoes lightly with butter mixture, reserving remaining butter mixture.
3. Grill potatoes, cut sides down, 4 minutes; turn, and grill 3 to 4 minutes or until tender. Remove from grill, and brush with remaining butter mixture.