Place vinegar and brown sugar in small saucepan over medium heat.  Whisk to blend.

Bring to a boil and cook until mixture is reduced by  more than half, about 20 minutes; mixture should have a syrupy consistency.  

Remove from heat, and allow to cool. Transfer to a container or  squeeze bottle to store.

Recipe published in JOY of KOSHER with Jamie Geller magazine Fall 2015. Subscribe Now.