To make the dressing, combine all ingredients in a bowl. Cover and place in the refrigerator to let the flavor develop. I'd ideally leave this overnight, but just do what you can. When it's time to prepare the salad, chop your potatoes into small chunks - the size depends on your personal preference but when using new potatoes I usually quarter them - and boil them in salted water until completely cooked. (15-20 minutes) Drain. (At this stage I like to add a little extra salt to the drained potatoes, but that's optional!) If you are serving this warm, leave the potatoes for about 15 minutes before stirring in the dressing and serving. If you are serving this cold, refrigerate the potatoes until they are completely cool and then combine with the dressing.