Wash potatoes. If using larger Yukon Golds, cut into 1 to 1-1/2 inch pieces so pieces are roughly uniform; small red potatoes can be halved or left whole if similar size. Leave skin on for texture.

Place potatoes in a large pot and cover with cold water by 1 inch. Add 2 tablespoons kosher salt. Bring to a simmer over medium-high heat and cook until potatoes are fork-tender, about 12–18 minutes depending on size.

Meanwhile, whisk together mayonnaise, sour cream, Dijon mustard, apple cider vinegar, sugar, and 1/2 teaspoon black pepper in a bowl until smooth. Taste and adjust seasoning; dressing should be slightly tangy and creamy.

When potatoes are tender, drain in a colander and let rest for 5 minutes to allow steam to escape (this helps dressing adhere rather than thinning). If you prefer a warm potato salad, allow only 5–10 minutes; for classic chilled salad, transfer to an ice bath to cool quickly, then drain.

Vegetables & Aromatics

While potatoes cook/cool, finely dice celery and red onion. Place diced vegetables in a small bowl and, if you want a milder onion flavor, sprinkle with a pinch of salt and let sit 5 minutes, then drain any liquid.

Chop fresh dill and slice chives. If using cornichons/dill pickles, dice small (about 1/4-inch).

Assembly & Finish

Transfer drained warm (or cooled) potatoes to a large mixing bowl. If pieces are large, roughly mash or gently break a few pieces with the back of a spoon so some potato is creamy and some are chunky; this helps the dressing cling.

Pour the dressing over the potatoes while still slightly warm so they absorb flavor. Add the diced celery, red onion, cornichons (if using), chopped dill, and chives. Gently fold with a rubber spatula or large spoon until evenly coated. Taste and add kosher salt and more black pepper as needed.

If using, fold in chopped hard-cooked eggs gently to avoid too much breakage.

Cover and refrigerate at least 1 hour to let flavors meld (overnight is best). Before serving, stir gently, adjust seasoning, and garnish with a sprinkle of smoked paprika or extra chopped dill and additional chives.

Transfer to serving quart container or bowl. This recipe yields approximately one quart (4 cups) of potato salad per the 'by the quart' sectioning.