• Step 1: Bring a large pot of salted water to a boil. Add the cubed potatoes and cook until tender, about 15-20 minutes. Drain the potatoes and let them cool completely.
• Step 2: In a large bowl, whisk together the mayonnaise, Dijon mustard, white vinegar, sugar, salt, and black pepper until well combined.
• Step 3: Add the cooled potatoes, chopped hard-boiled eggs, diced celery, diced onion, and sweet pickle relish to the dressing. Gently fold everything together until the potatoes are evenly coated.
• Step 4: Cover the potato salad and refrigerate for at least 2 hours, or up to 3 days, to allow the flavors to meld.
• Step 5: Serve the potato salad chilled or at room temperature, garnished with additional chopped hard-boiled eggs or fresh parsley, if desired.