Scrub the dirt off the potatoes and cut them so they are approximately ½-inch to ¾-inch thick. Place them in a large pot along with plenty of salt and cover them with cold water by about 1 inch. Bring to a boil and cook until fork tender.
Drain the potatoes (don't rinse them) and add to a large bowl to let them cool slightly.
Peel the eggs under cold water and cut them in half. Add the yolks to a small bowl and set aside. Cut the whites into ½-inch pieces and add to the potatoes.
Using a fork, mash the egg yolks and add the yogurt, lemon juice, olive oil, salt and pepper. Stir in the chopped onions, pickles, dill, and capers.Mix well to combine and stir into the potato mixture, coating the potatoes well. Taste for seasoning and adjust if necessary.
Transfer to a serving dish and garnish with sprigs of dill.
Video
Notes
Cook the potatoes until tender and still a little firm. The tip of a sharp knife should have a little resistance when the potato is pierced
You may not need to use all of the dressing initially but keep in mind that the potatoes will soak it up over time, so you might want to add more later. If you have any dressing left over, cover it and refrigerate it. It will keep for 3 to 5 days.