This is a Niçoise-inspired potato salad, using many of the ingredients found in that traditional French dish. Instead of using a classic mayo-based dressing, this potato salad calls for a lighter vinaigrette featuring spicy Dijon mustard.
Add the chopped potatoes to a medium-sized pot and add just enough water to cover them fully. Boil the potatoes, covered, over medium-high heat until they are fork-tender (about 15-18 minutes). Transfer the potatoes to a colander to drain and then rinse with cold water to stop them from over-cooking. Refridgerate the potatoes until they're fully cooled.
When you're ready to assemble the salad, whisk together the olive oil, vinegar, mustard, salt, and pepper (to taste) the bottom of your serving bowl and toss with the potatoes, olives, capers, and parsley.