How to Make It
Stir together the crème fraîche, yogurt, lemon zest, juice, water, and ¾ teaspoon of the salt.
Place the potatoes in a large pot with salted water to cover and bring to a boil over high. Reduce heat to medium-low and simmer until tender, about 16 minutes. Drain and place in a single layer on a platter. Using a fork, gently smash the tops of the potatoes just until they begin to break apart. Sprinkle the potatoes with the remaining salt.
Top the potatoes with the crème fraîche mixture, dill, and cracked pepper.