At first I though this was a gimmick since, for the last decade, it's seemed like the Italians have been trying to get balsamic vinegar injected into every food in sight.  Turns out this invasion is an excellent innovation.  It kind of makes sense since cooked grape must-the base of balsamic vinegar-was traditionally a sweetner in Italy.

The balsamic is laced through the cake, forming a ribbon of dark glaze. Instead of finding panettone's traditional gems of dried fruit, you'll discover veins of cherry-sweet, luscious caramel. If you're a panettone beginner-or traditionalist-this probably isn't the cake for you. Go for the standard panetttone. But if you're looking to expand someone's horizons this makes a great gift. Like with all pannettoni the packaging is stunning.

"The perfect panettone"
Charles Passy, Wall Street Journal