Place 1½-2 inches of water in the bottom of a large pot. Place a steamer basket in the pot and add the cut potatoes to the basket. Bring the water to a boil over high heat and then reduce the heat to medium-high. Cover and steam the potatoes until knife-tender, stirring once or twice to ensure the potatoes in the center are evenly cooked, about 25-30 minutes.
Transfer the potatoes to a large bowl. Let cool at least 30 minutes before dressing; the potatoes should be room temperature. Meanwhile, make the dressing.
Place the chives, dill, and parsley in a medium bowl and stir to combine. Remove 3 tablespoons of the mixture to a small bowl and set aside for garnish.
Add the buttermilk, mayonnaise, vinegar, lemon zest, and salt to the medium bowl of herbs. Season with pepper and whisk to combine. Refrigerate the dressing until the potatoes are ready.
Add the apples to the potatoes. Pour the buttermilk dressing on top and fold it in gently until fully dressed. Season to taste with salt and pepper. Transfer to a large serving bowl. Scatter the reserved herb mixture on top.
Make ahead: The potato salad can be made and stored in an airtight container in the refrigerator up to a day ahead. Garnish with the fresh herbs just before serving.
- 1½ pounds new potatoes, peeled and quartered
- 1 pound blue potatoes, quartered
- 2 Cosmic Crisp® apples, skin on, cored and cut into chunks the size of the potato pieces
- ¼ cup finely chopped fresh chives
- ¼ cup coarsely chopped fresh dill
- ¼ cup coarsely chopped fresh Italian parsley leaves
- ½ cup mayonnaise
- ¼ cup buttermilk
- 1 teaspoon apple cider vinegar
- ¾ teaspoon lemon zest
- 1 tablespoon dried chives
- 1 teaspoon kosher salt, plus more for taste
- Freshly cracked black pepper to taste