Place sour cream, buttermilk, Parmesan, garlic, vinegar, pepper and salt into a blender or food processor and blend until well combined.
Transfer to a container with a tight-fitting lid and refrigerate for at least one hour for best flavor. Note: Adjust amounts of salt and pepper to taste. If a thinner consistency is desired, add more buttermilk. To thicken, add equal parts of sour cream and parmesan.
