Boil the Potatoes
In a large pot, cover cubed potatoes with water and bring to a boil.
Add a pinch of salt and simmer for 12–15 minutes until fork-tender.
Drain and let cool slightly.
Prepare the Dressing
In a small bowl, whisk together mayonnaise, Dijon mustard, vinegar, lemon juice, salt, and pepper.
Combine Ingredients
In a large bowl, gently mix potatoes, celery, onion, parsley, and dill.
Add the dressing and toss until evenly coated.
Chill Before Serving
Cover and refrigerate for at least 30 minutes for flavors to meld.
Taste and adjust seasoning if needed before serving.