Place the cubed potatoes in a large pot and cover with cold water. Add a pinch of salt and bring to a boil over medium-high heat. Cook until the potatoes are fork-tender, about 10-15 minutes. Drain and let cool completely.

In a large mixing bowl, combine the mayonnaise, Dijon mustard, apple cider vinegar, garlic powder, onion powder, salt, and black pepper. Mix until smooth.

Once the potatoes have cooled, add them to the bowl with the dressing. Gently fold in the celery, red onion, hard-boiled eggs, and parsley until everything is well combined.

Taste and adjust seasoning if necessary. Cover the salad and refrigerate for at least 1 hour to allow the flavors to meld.

Serve chilled or at room temperature.