Before you read any further, and want to comment, go down and write what you think it is in the comment section then come back up and read the answer.
Wrote it down?
Well here is the answer.
Now, before you go "YUCK!!" or "WHAT?!" hear me out =) First off, it's an Italian dessert, and we all know that the Italians love their oil and vinegar. So why not put vinegar on your dessert?
The second thing is that you don't use cheap vinegar. You use dessert vinegar, which is way more expensive, and sweeter that your average bottle. Like "cheap" expensive balsamic vinegar starts at $20 for a 5-year-aged, 150 ml bottle. Why is it more expensive when it's only aged 5 years? Because vinegar is like wine and cheese. The longer it's aged, the more expensive it is.
The third thing is it doesn't taste like vinegar on ice cream like you'd think. In the words of my dad, it tastes a little like blueberry syrup instead on vinegar (at least the dessert vinegar does). And you don't eat 3 scoops of this dessert. You eat a small bowl full. It's not somthing you consume in large quantities, but in small portions... around one scoop.
And while some people like the dessert vinegar is prefered by my mom and dad, I actually like the sharp tang of normal balsamic vinegar. I like vinegar in general, but for those of you who don't, but want to try something different, this is the dessert for you =) Just use dessert vinegar.
Now you'll want to try it. Go ahead. People will think you weird at first. Like you probably do me. But it's one of those things that you have to try before judging. I will say it's an acquired taste, so don't make a bunch, or buy a really expensive bottle at first! Let me know if you do try it, and what you think =)
*oh, and it's really only good on vanilla ice cream. Not really on chocolate, though you could try a teaspoon before making that assumption. But do it after having it with the vanilla ;)