Place the peeled and cubed potatoes into a large pot. Add enough cold water to cover the potatoes by about an inch. Stir in 1 tablespoon of Kosher salt.

Bring the water to a boil over medium-high heat. Once boiling, reduce heat to a simmer and cook for 15-20 minutes, or until the potatoes are fork-tender but still hold their shape. Do not overcook.

Carefully drain the potatoes in a colander. Spread them out on a baking sheet or large platter to cool completely. This helps dry them out slightly, preventing a watery potato salad. Cooling can take 30-60 minutes at room temperature; ensure they are fully cool before proceeding.

While the potatoes are cooling, prepare the dressing. In a large mixing bowl, combine the mayonnaise, finely chopped celery, finely diced red onion, chopped hard-boiled eggs, Dijon mustard, apple cider vinegar, granulated sugar, and freshly ground black pepper.

Gently fold all the dressing ingredients together until well combined.

Once the potatoes are completely cool, add them to the bowl with the dressing. Gently fold the potatoes into the dressing until they are evenly coated. Be careful not to mash the potatoes.

Taste the potato salad and adjust seasoning as needed, adding more salt, pepper, or a pinch more sugar or vinegar if desired.

Cover the bowl tightly with plastic wrap and refrigerate for at least 2 hours, or preferably overnight, to allow the flavors to meld. Chilling is crucial for the best flavor and texture.

Before serving, give the potato salad another gentle stir. Garnish with fresh chopped dill or parsley for a pop of color and freshness.