Combine 1/4 cup of the vinegar and the remaining ingredients in a saucepan and whisk well. Bring to a low boil over medium heat, stirring continuously as it thickens.
Add more vinegar to taste. Continue cooking until you get the thickness you desire, about 5-10 minutes.
Remove from heat, and cool completely.
Notes
Will keep for up to 6 months refrigerated in a sealed container.