Boil potatoes with skins on until just tender, not mushy
Peel while warm and slice into thin rounds
Place minced onion into a large bowl
Pour hot broth over it, add vinegar, salt, pepper, and sugar
Add warm potato slices and gently combine
When cooled slightly, fold in the oil
Taste and adjust seasoning — the salad should be slightly glossy and juicy
Top with parsley and serve warm or at room temperature
