1. Place the Cherry Preserves in a sauce pan over medium heat until it melts. Add the Blacken and vinegar and stir it up good. Let this simmer for about 5 minutes.
2. Blend with a food processor, blender, or an immersion blender (like I did). The whole cherries blended, will help thicken the sauce.
As it cools, it'll thicken because you've boiled off some of the water in the preserves, this is when you add the port wine. Add enough so that you've got a nice basting sauce. Set this aside while you cook the Pork.