In a small saucepan over medium heat, add the vinegar and sugar and stir until dissolved.
2 cups Balsamic vinegar, ½ cup Brown sugar
Bring to a light boil, then reduce heat to medium-low. Stirring regularly, let simmer until the vinegar reduces by half or more, about 10 minutes. It should be thick enough to coat the back of a spoon.
Remove from the heat and allow to cool completely, about 15 minutes. Then store or serve, and enjoy!
Notes
Add extra seasonings of your choice like garlic, herbs, and red pepper flakes.
You'll know when the sauce has reduced enough when it can coat the back of a spoon without immediately running off.
This is balsamic glaze, not a balsamic reduction. To make a reduction, skip the sugar and instead add in extra seasonings of choice, such as rosemary, garlic, and red pepper.
If substituting honey, let it simmer a little longer. The added liquid in honey balsamic glaze can take longer to reduce.