Cut the potatoes into even cubes and boil in salty water until just cooked through, a knife should slide in with a little resistance rather than passing through cleanly like when making mashed potato. You want them holding their shape, not collapsing.

Drain and leave to steam dry for a few minutes. While still warm, transfer to a large bowl.

Mix the mayonnaise, balsamic vinegar, salt and a generous amount of black pepper in a separate bowl. Pour over the warm potatoes and fold through gently to coat, being careful not to break them up.

Add the parsley and chives and fold through once more. Taste and adjust the seasoning.

Serve warm or at room temperature. If making ahead, dress the potatoes while still warm, then cover and refrigerate. Bring back to room temperature before serving and loosen with a little extra mayonnaise if needed.