Ingredients:

2 lb. potatoes boiled in their skin and cooled.
Brine:
1 C. white vinegar
1 1/3 C. water
3/4 C. sugar
1 onion, chopped
salt and pepper to taste
Dressing:
1/2 C. Hellman's mayonnaise
3/4 C. sour cream
2 1/2 T. tarragon-flavored vinegar
1 1/2 t. salt
3/4 t. celery seed
Salad:
4 C. cold, boiled potatoes, peeled, diced
3/4 C. sliced green onions
1 sm. jar chopped pimentos
3 hard-cooked eggs, chopped

Combine brine ingredients and boil for 5 min. slice potatoes thin and pour hot brine over them. Let them marinate for 24 hours. Drain in colander but do not drain dry. Add Hellman's mayonnaise, enough to make it as creamy as you like. It is better to make it the day before, or even 2 days before.
Dressing: Mix well and refrigerate while making the rest of the salad.
Salad: Mix potatoes, onions in bowl. Drain pimentos well and then put on a paper towel so that the salad doesn't turn pink. Add eggs. Mix dressing gently with all the above stuff and keep refrigerated until ready to serve. Doubling this recipe is a good idea - people keep sneaking into the refrigerator for samples.

Source: razzledazzlerecipes.com