Thinly slice the core end of the romaine, just to clean it up, being careful not to cut the whole end off. Then cut lengthwise down the middle of romaine making two equal halves.
Brush each half on both sides with olive oil, place cut side down on grill. Grill only a couple of minutes, just until leaves begin to wilt and turn slightly brown with grill marks. Turn and repeat on other side.
Remove from grill and place cut side up on each serving plate.Drizzle with balsamic vinegar and a little more olive oil.
Sprinkle with kosher salt and fresh ground pepper, to taste. Top with crumbled bacon and shredded parmesan.