1½ kilograms waxy potatoes, scrubbed
¼ cup good white wine vinegar
¼ cup white wine
2 tablespoons wholegrain mustard
¼ cup finely chopped red onion
4 tablespoons olive oil
¼ cup finely chopped cornichons or gherkins
2 tablespoons each chopped basil and flat-leaf parsley
sea salt and freshly ground pepper
Cook the potatoes in a saucepan of boiling, well salted water until tender when pierced with a skewer. Drain in a colander, cover with a clean tea towel and leave to steam for 10 minutes.
Whisk the vinegar, wine and mustard in a large bowl. Cut the warm potatoes in half or into quarters if large and add to the vinegar mixture, turning gently to combine. Leave for at least 10 minutes for the potatoes to absorb the flavours.
Soak the red onion in a bowl of cold water for 10 minutes. Drain and squeeze dry in a clean tea towel. Drizzle the olive oil over the potatoes then add the onion, cornichons and the herbs. Season well and gently turn to combine. Transfer to a serving bowl. The salad is best served freshly made. If making the salad ahead, cover and refrigerate but bring back to room temperature before serving.