Step 1

Place potatoes into an 8-quart pot, cover with cold water, and place over medium heat. Cover the pot and bring to a boil. Immediately reduce the heat and remove the lid. Gently simmer until potatoes are fork tender, 10 to 15 minutes. Drain and place in an ice bath to cool for 2 to 3 minutes. Remove the skin by rubbing with a clean tea towel. Slice the potatoes into rounds or cut into large dice and place into a zip-top bag. Add the vinegar and toss to coat all of the potatoes. Place the bag into the refrigerator overnight.

Step 2

In a large mixing bowl, combine the mayonnaise, mustard, parsley, tarragon, garlic, cornichons, onions, and celery. Once evenly combined, add the potatoes, toss, and season with salt and pepper. Let the salad chill in the refrigerator for at least 1 hour before serving.