While the Brussels sprouts roast, combine the Balsamic Vinegar and honey in a small pan
and bring to a boil over medium/high heat. Then, reduce the heat to med or med//low so that the vinegar is just lightly simmering. Simmer until reduced by half, and the vinegar coats the back of the spoon, about 10 minutes.* Set aside to thicken and cool while the Brussels finish roasting.