Bring a large pot of salted water to a rolling boil over medium-high heat. Add two pounds of quartered new potatoes and boil for about 15 minutes, or until tender. Drain and let cool slightly.

In a medium bowl, whisk together finely chopped red onion, parsley, and apple cider vinegar. Drizzle in olive oil while whisking to emulsify. Stir in Dijon mustard, sugar, salt, and black pepper.

While the potatoes are warm, transfer them into the bowl with the dressing and gently toss to coat.

Serve the warm potato salad in a vibrant dish immediately for best flavor.