Make Buttermilk Dressing and chill before cooking potatoes.

Buttermilk Dressing: Combine first 7 ingredients in blender or food processor. Process until well combined. Add remaining ingredients. Process until smooth. Chill.

Dinner Potatoes: Fill a large pot about half full of water. Cover and turn the heat to high. There should be plenty of water for the potatoes to move around in. While water is coming to a boil, scrub potatoes. Take 1 inch of the peeling off around center of potatoes. Carefully add the potatoes to the boiling water. Add salt. Boil about 15 minutes until they yield easily to a toothpick. Drain and put them in an electric mixer with the paddle attachment. Add butter and run the mixer just enough to smash the potatoes into chunky pieces, do not over mix. This is a rough chop.

Add dressing to potatoes, stir and serve.