Balsamic Glaze (Reduction)
2 cups good quality balsamic vinegar
1/2 cup brown sugar (optional)
Heat balsamic vinegar in a small pot or saucepan over medium heat.
If adding sugar*, combine both into the pot and heat together.
Bring to a gentle boil, then reduce heat to medium-low heat and let simmer, stirring occasionally, until the vinegar thickens and is reduced by half (about 20 minutes). It should be thick enough to coat the back of a spoon.
*If simmering with sugar, it will take about 8-10 minutes to reduce.
Remove from heat and allow to cool completely before serving (about 15 minutes).