Prepare a fire in a charcoal grill. Trim a slice from the top of each Vidalia Onion, and peel the Vidalia Onion without cutting off the root end. With a potato peeler, cut a small cone-shaped section from the center of the Vidalia Onion. Cut the Vidalia Onion into quarters from the top down, stopping within a half inch of the root end. Place a bouillon cube in the center, slip slivers of butter in between the sections, and sprinkle with pepper.
Wrap each Vidalia Onion in a double thickness of heavy-duty foil. Place the Vidalia Onions directly onto the hot coals and cook for 45 minutes, turning every so often. Or, bake the foil-wrapped Vidalia Onions in a 350°F oven for about 45 minutes. Serves one onion per person.