Place the potatoes in a pan and cover with cold water. Bring to the boil and simmer for 7-9 minutes until tender.
Drain the potatoes and leave to cool.
Place the cooled potatoes in a bowl with the onion, mayonnaise, salad cream, half of the white pepper and the salt. Stir everything together to combine. Taste and add a little more seasoning if needed.
Cover and refrigerate for at least 30 minutes (up to a day) before serving. Just before serving sprinkle with chopped chives and a little black pepper if you like.