Remove papery skin from onions. Slice onions in quarters from top to bottom so each quarter includes some of the core to hold it together.
Set quarters in a small baking dish, pointy side up. Season with salt and pepper, add stock and balsamic and top with herbs. Cover tightly with aluminum foil and bake for 45 minutes. Remove foil and bake for 30 more watchful minutes or until onions are very caramelized and the liquid is reduced to a thick glaze.