In a pot over high heat, heat all the ingredients and stir. Bring to a boil then lower to a simmer for 10 to 15 minutes (make sure it’s actually simmering the entire time). You want it thick enough to coat the back of a spoon, but not to thicken into a glob.
Allow the mixture to cool completely, it becomes thicker once it has cooled. It'll be about the consistency of maple syrup.
The glaze can be stored in the refrigerator in a sealed jar once it has cooled down for at least a month. Enjoy!
Notes
How to store: Store balsamic glaze in a sealed container in the refrigerator for up to a month.