Peel and chop the potatoes into small pieces

Boil the potatoes in salted water until still firm, but you can run a fork through them.

Drain the potatoes and transfer to a large bowl.

Peel and dice the onion and mix it with the potatoes

Puree 2 cups of the arugula and the apple cider vinegar in a food processor or blender.

Add the mayonnaise and sugar to the arugula mixture. Pulse until just combined.

Season with kosher salt and freshly ground pepper to taste.

Toss the potatoes and onions with the arugula cream.

Season again with salt, pepper, and sugar to taste.

Roughly chop the remaining 1/2 cup of arugula, fold it into the potato salad, and serve.