This is from an old edition of the Joy of Cooking
2lbs potatoes, cook until tender and cut into bit size pieces
For dressing:
Whisk together:
6 tablespoons red or white wine vinegar
1shallot or 1/2 onion minced or 3 tablespoons chives
2 tablespoons fresh parsley
2 tablespoons drained capers
1 tablespoons whole grain mustard
1 tablespoon minced fresh tarragon, dill, mint or thyme
Salt and pepper to taste.
Add in a slow steady stream:
6 tablespoons olive oil
Pour dressing over still warm potatoes and toss gently.
This makes a lot of dressing so you may not want to use it all but the warm potatoes seem to absorb it and all the herbs are so good.