
Slice the stem from the onions and peel them, leaving the root intact. Slice a bit of the root off, just enough to provide a flat end so they won't wobble.
Working from the top and using a sharp knife, a small melon baller, or apple corer, cut the cores from the onions.
You should have a cavity about 1 inch across and almost through to the bottom of the onion without piercing it. Use the cored-out onion pieces for another purpose.
Salt and pepper the onion cavities and then fill each onion with 1 tablespoon of oil. Sprinkle the onions lightly with a bit more salt and pepper. Wrap the onions in foil, gathering at the top and twisting to seal.
Leave them on the grill for more smoked flavor, if you like.
