Heat the balsamic in a small saucepan over medium heat.
When heated and starting to simmer, add the sugar and salt to the balsamic. Stir to combine.
Cook the balsamic mixture, stirring occasionally, at a simmer until reduced by half, approximately 15 minutes. It will be thicker than it was before, but not sticky thick until it cools down some. It should coat the back of the spoon.
Let the balsamic glaze cool to room temperature and then chill. It will thicken up more when cool. If yours is still not thick, you can throw it back in a pan to continue cooking. Store in a glass jar or container in the refrigerator.
Notes
Balsamic can be expensive, but for this recipe you do not need to use the fancy stuff. Any type or quality of balsamic will work out just fine.To get the glaze extra thick like in the picture, it needs to be cool. I make mine and chill it in the refrigerator for at least 30 minutes and you will get that perfect, thick glaze.