Step 1

Place the potatoes in a large saucepan with water to cover by 2 inches. Add 2 tablespoons salt and bring to a boil. Lower the heat and simmer for 10 to 12 minutes, until just barely tender when pierced with a fork. Set aside ⅓ cup of the cooking liquid, then drain the potatoes and place them in a large bowl. Drizzle the potatoes with the vinegar and reserved cooking liquid and let them stand for 10 minutes, tossing occasionally.

Step 2

Meanwhile, in a medium bowl, combine the celery, shallots, cornichons, chives, and dill and set aside. In a small bowl, whisk together the mayonnaise, sour cream, 1 teaspoon salt, and ½ teaspoon pepper. Add three quarters of the vegetable-and-herb mixture to the potatoes, reserving the rest. Stir in the mayonnaise dressing, incorporating any liquid in the bowl, and cool to room temperature. Cover and refrigerate for at least 2 hours for the flavors to blend.

Step 3

When ready to serve, add the reserved vegetable mixture and the eggs to the salad and sprinkle with extra dill, salt, and pepper. Stir gently to combine. Taste for seasonings and serve cold or at room temperature.