Step 1

Place potatoes in a medium saucepan of cold salted water. Place over high heat. Bring to the boil and cook for 8-10 minutes or until potatoes are just tender.

Step 2

While the potatoes are cooking, combine the eschallot, mustard, sugar, vinegar and oil in a bowl large enough for the potatoes. Reserve one-quarter of the dressing for serving.

Step 3

Drain the potatoes and when cool enough to handle, slice into 1cm-thick slices. Add to bowl with dressing and gently toss to coat. Set aside to cool for 10 minutes.

Step 4

Just before serving, add herbs and gently toss again. Season with salt and freshly ground black pepper. Drizzle over reserved dressing and top with extra fresh tarragon leaves.