Scrub the potatoes and cut any very large ones into uniform 1- to 1.5-inch pieces. Place potatoes in a pot and add enough cold water to cover by 1 inch. Add 1 tablespoon kosher salt. Bring to a gentle boil, then reduce to a simmer and cook until potatoes are fork-tender, about 12–15 minutes depending on size. Drain thoroughly in a colander and let steam-dry for 5 minutes. Transfer to a large bowl and let cool slightly (warm is ideal so potatoes absorb dressing).

Season potatoes lightly with freshly ground black pepper (about 1 tsp) while still warm to help flavor penetrate.

Dressing

Make dressing

In a medium bowl, whisk together 3 tablespoons mayonnaise, 1 tablespoon Dijon mustard, 1 teaspoon whole-grain mustard, 1 tablespoon apple cider vinegar, 1 teaspoon sugar, 1 teaspoon salt, 1 teaspoon celery seed and 1 teaspoon olive oil until smooth and well combined. Taste and adjust seasoning — it should be bright, slightly tangy and just a touch sweet.

Mix-ins & Garnish

Cook and prepare eggs

Place 2 large eggs in a small saucepan and cover with cold water by 1 inch. Bring to a gentle boil, then turn off heat and cover; let sit 9–10 minutes for fully set hard-boiled eggs. Transfer eggs to an ice bath for 5 minutes, peel, and finely chop (or halve for garnish).

Combine salad

To the bowl with warm potatoes, add the prepared dressing and gently fold to coat, being careful not to mash the potatoes. Add the chopped hard-boiled eggs, 3 finely diced small pickles (or cornichons), 1/4 cup finely diced red onion, 1 finely diced celery stalk, 2 tablespoons chopped parsley and 2 tablespoons sliced chives. Gently fold until evenly distributed. Taste and adjust salt and pepper as needed.

Transfer potato salad to a serving bowl, sprinkle 1/2 teaspoon sweet paprika over the top and garnish with reserved egg halves or extra chives and parsley if desired. Chill 30 minutes for flavors to meld or serve at room temperature.