Begin by peeling the russet potatoes, then cut them into uniform ¾-inch cubes. Place the diced potatoes into a large pot and fill it with cold water, enough to cover the potatoes by about an inch.

Bring the pot of water to a rolling boil, add a pinch of kosher salt, lower the heat, and cook for about 8 to 10 minutes until fork-tender. Drain and return to pot.

While the potatoes are still warm, drizzle the distilled white vinegar over them and stir gently to coat. Let sit for 20 minutes.

In a large mixing bowl, combine the marinated potatoes with mayonnaise, chopped celery, dill pickle relish, diced red onions, minced parsley, yellow mustard, black pepper, and onion powder. Stir gently.

Cover the bowl with plastic wrap and refrigerate for at least 1 hour. Stir and garnish with extra parsley and celery before serving.