2 lb Idaho potatoes (about 3 large), scrubbed
Kosher salt with white pepper

Pesto:
1 small bunch flat-leaf parsley (about 1/2 ounce), with about 1 inch of stems still attached, roughly chopped
Kosher salt and white pepper
3 tablespoons extra-virgin olive oil

Dressing:
2 tablespoons red wine vinegar
1 shallot, sliced into thin rounds
1 tablespoon Dijon mustard
2 teaspoons chopped capers, plus 1 teaspoon of their brine
4 cornichons, quartered lengthwise and sliced into 1/4 inch pieces, plus 1 tablespoon of their brine
1/3 cup extra-virgin olive oil

2 lb Idaho potatoes (about 3 large), scrubbed 1 small bunch flat-leaf parsley (about 1/2 ounce), with about 1 inch of stems still attached, roughly chopped 3 tablespoons extra-virgin olive oil 2 tablespoons red wine vinegar 1 shallot, sliced into thin rounds 1 tablespoon Dijon mustard 2 teaspoons chopped capers, plus 1 teaspoon of their brine 4 cornichons, quartered lengthwise and sliced into 1/4 inch pieces, plus 1 tablespoon of their brine 1/3 cup extra-virgin olive oil

1. preheat oven to 400 degrees

Baking the potatoes:

2. Arrange the potatoes in single layer on a baking sheet. Bake until the potatoes are tender and yielding when pierced in the thickest part with the tip of a knife, about 1 hour

Make the Pesto:

3. Meanwhile, in a food processor or blender, combine the parsley and basil. Season with salt and pepper, add 2 tablespoons water and blend. With the machine running, pour the olive oil through the top of the processor in a slow steady stream. the texture should be a little rustic and chunky. Taste for seasoning.

Make the dressing:

4. In a bowl large enough to hold the potatoes, whisk together the vinegar, shallots, mustard, capers, and brine, and gherkins and brine with 1 tablespoon water. Whisk in olive oil. Taste for seasoning.

Finish the salad:

5. Once the potatoes are cool enough to handle, peel half of them. (Some potato skin is a nice flavor in the salad). Put the potatoes in the large bowl with the dressing and lightly crush them with the tines of a fork. Season lightly with salt and pepper and toss them in the dressing. Drizzle with the pesto and stir to blend. Serve warm or at room temperature