The key to the deeply-seasoned potatoes in this tangy and creamy salad is to cook them in water seasoned with salt and vinegar. A dressing flavored with olive oil, sour cream, and dill binds it together.
Why this recipe works:
- Adding salt and vinegar to the potato cooking water not only seasons the potatoes deeply, but the vinegar also prevents them from falling apart as they cook.
- Seasoning the potatoes with more vinegar while they're still hot is key to deep flavor penetration and a light texture on the palate.
- 1 1/2 pounds fingerling potatoes (such as La Ratte or Russian Banana), cut into 1/2-inch disks
- Kosher salt
- 2 tablespoons white wine vinegar, divided
- 1 tablespoon whole grain mustard
- 2 tablespoons sour cream
- 2 teaspoons extra-virgin olive oil
- 1 small red onion, diced (about 3/4 cup)
- 2 scallions, finely sliced (about 1/4 cup)
- 2 tablespoons minced fresh dill
- Freshly ground black pepper
Place potatoes, 1 tablespoon salt, 1/2 tablespoon vinegar, and 3 cups tepid water in a medium saucepan. Bring to a boil over high heat, stirring occasionally until salt is dissolved. Reduce to a bare simmer and cook until potatoes are completely tender and show no resistance when poked with a paring knife or cake tester, about 17 minutes. Drain potatoes. Immediately toss potato pieces with 1 tablespoon vinegar, spread in a single layer in a rimmed baking sheet, and allow to cool to warm room temperature, about 10 minutes.
Meanwhile, combine mustard, sour cream, olive oil, red onions, scallions, dill, and remaining 1/2 tablespoon vinegar in a large bowl and whisk together. Add potatoes and toss thoroughly to combine. Season to taste with more salt and pepper as necessary. Serve. Potato salad can be stored in the refrigerator for up to 5 days. Allow to come to room temperature before serving.