- 3 pounds Yukon Gold potatoes, scrubbed
- Kosher salt
- 1 cup mayonnaise
- ¼ cup greek yogurt
- 2 tablespoons white wine vinegar
- 2 tablespoons Dijon mustard
- 2 tablespoons whole-grain mustard
- 3 tablespoons finely chopped flat-leaf parsley
- 3 tablespoons chopped dill
- 3 tablespoons snipped chives
- Freshly ground black pepper
- ½ cup finely chopped red onion (or thinly sliced scallions)
- Put the potatoes and 2 tablespoons of salt in a large saucepan, cover with water and bring to a boil. Simmer the potatoes over moderate heat until tender, about 25-30 minutes. Drain the potatoes in a colander, then place the colander with the potatoes over the empty pot and cover with a clean, dry kitchen towel. Allow the potatoes to steam for 15 to 20 minutes.
- Meanwhile, in a small bowl, whisk together the mayonnaise, yogurt, vinegar, Dijon mustard, whole grain mustard, herbs, and salt and pepper to taste (approx. ½ -1 tsp of each). Set aside.
- When the potatoes are cool enough to handle, cut them into 2 inch chunks. Place the cut potatoes in a large bowl. While the potatoes are still warm, pour enough dressing over them to moisten well. Add the celery (if using) and red onion. Toss well, cover, and refrigerate for a few hours or overnight. Serve cold or at room temperature.