Combine all of the ingredients in a small bowl, and mix well.
You can also cut this in half and use on of the small 6 oz. cans of tomato paste, if you don't want so much. But store it in a cleaned out ketchup or mustard bottle, and it will keep in the fridge for months.
We LOVE balsamic vinegar, but if you think this might be too strong for you, then you can cut the amount and add in a little water to get the consistency you want. But the flavor does mellow as it sits.
Recipe by Cupcakes & Kale Chips at http://cupcakesandkalechips.com/2012/04/26/balsamic-ketchup-recipe/