Boil the potatoes in their skins in a pan of salted water for about 6 minutes. Then take the pan off the heat and leave the potatoes to stand in the cooking water, covered, for about 15 minutes, depending on their size. Test with a skewer that the potatoes are tender before draining off the water – if not, leave them a little longer.
Peel the potatoes, then cut them into bite-sized pieces.
Mix the ingredients for the dressing and season to taste with salt and freshly ground pepper. If you like, add a pinch of sugar – it suits the dressing well.
Toss the potatoes in the dressing and keep the potato salad in the fridge until ready to serve.