Place the whole, unpeeled potatoes in a large pot of water. Bring to a boil, then lower the heat and simmer for 10-15 minutes, until fork tender. Drain and cover to steam for 5-10 minutes. Peel if desired and cut into 1/2 inch chunks.

Separate egg yolks from the whites, mash yolks, and stir in mayonnaise, buttermilk, mustard, splash of pickle juice, salt and pepper to taste.

Pour dressing over warm potatoes. Chop egg whites, add to potatoes along with celery, onion, and pickles. Stir well, cover and refrigerate for a few hours to blend flavors.