American
Peel the potatoes and cut them into 2 cm cubes. Cover with cold salted water, bring to a boil and simmer until just tender, 10-12 minutes.
Drain the potatoes, spread them on a tray and sprinkle with the vinegar while still warm. Let them cool for 20 minutes.
Boil the eggs for 10 minutes, cool them in cold water, then peel and chop.
Finely dice the celery and red onion.
Whisk the mayonnaise, mustard, relish, sugar, salt and pepper in a large bowl.
Add the potatoes, eggs, celery and onion and fold gently until coated.
Cover and chill for at least 60 minutes, then dust with paprika before serving.