Herby Green Goddess Potato Salad

Place 2 lb. small potatoes, preferably tricolored peewees, scrubbed, in a large pot and pour in water to cover by at least 2". Add a generous pinch of kosher salt and set over high heat. Bring to a boil, then reduce heat to medium and simmer until fork-tender, 15–20 minutes. Drain potatoes in a colander and let sit until cool enough to handle.

Meanwhile, coarsely chop 8 scallions, 3 garlic cloves, 1 cup (lightly packed) dill sprigs, and 1 cup (lightly packed) parsley leaves with tender stems, and place in a blender. Add zest and juice of 1 lemon, 1½ cups mayonnaise, 1 cup sour cream, ¼ cup extra-virgin olive oil, 3¼ tsp. Diamond Crystal or 2 tsp. Morton kosher salt, and 1½ tsp. freshly ground pepper and blend on high speed until smooth, about 2 minutes. Pour dressing into a large bowl.

Cut potatoes in half lengthwise and add to dressing. Thinly slice remaining 2 scallions on a diagonal; finely chop remaining ½ cup (lightly packed) dill sprigs and remaining ½ cup (lightly packed) parsley leaves with tender stems. Transfer about ¼ cup scallion mixture to a small bowl and set aside for serving. Add remaining scallion mixture to potato salad and toss until potatoes are evenly coated in dressing and scallion mixture. Taste potato salad and add more salt if needed. Cover and chill at least 2 hours.

When ready to serve, top potato salad with reserved scallion mixture. Season with more pepper and drizzle with more oil if desired. Do Ahead: Potato salad (without toppings) can be made 12 hours ahead. Keep chilled. Cover and chill reserved scallion mixture separately.