Step 1

Wash and scrub the potatoes and dry them well. Slice potatoes thinly using a mandoline slicer. I used this slicer (affiliate link).

Step 2

Place potatoes in a pot and add water to cover by 1 inch. Bring to a boil. Add salt. Turn the heat down and allow the potatoes to simmer for about 6 minutes or so until they're tender (you should be able to poke the potatoes with a fork).

Step 3

Add vinaigrette ingredients to a small bowl and whisk until well-combined.

Step 4

When the potatoes are ready, remove from heat and drain well. Place them in a large mixing bowl and immediately dress them with the Dijon mustard dressing. Gently toss to coat.

Step 5

Add onions, fresh herbs, and capers. Toss gently to combine.

Step 6

Transfer the potatoes to a serving platter. For best results, allow the potato salad some time to marinade before serving. You can refrigerate it for 1 hour or so but be sure to bring it to room temperature before serving.