I had leftover sparkling wine and so set out to make this. Opened the pantry and no balsamic vinegar! Undaunted, I used Chinkiang black vinegar, which has a similar flavor profile. Gave it more of an earthy note, but still interesting.
I made it with Uncle Val's Botanical, Dolin, Cointreau, Grande Absente. Quite interesting and very good, though next time I will use a different gin--Val's tends to overpower.