Start by placing the peeled and cubed potatoes in a large pot, covering them with cold water, and adding 1 tsp sea salt. Bring to a boil, then reduce heat and simmer for 15-20 minutes until the potatoes are fork-tender but not falling apart. While the potatoes cook, prepare your mise en place: finely dice the red onion and soak it in cold water for 10 minutes to mellow its bite, then drain well. Finely chop the celery stalks, mince the dill pickle, and chop the fresh herbs (parsley and dill). Set all prepped ingredients aside in separate bowls.

In a separate bowl, whisk together the sour cream, mayonnaise, yellow mustard, celery seed, and granulated sugar until smooth and well combined. This creates a creamy, flavorful base that will coat all the other ingredients. Set the dressing aside—it will be added to the warm potatoes to help them absorb the flavors better.

Drain the cooked potatoes in a colander and immediately transfer them to a bowl of ice water for 2-3 minutes to stop the cooking process—this keeps them from becoming mushy. Drain the potatoes again and return them to a large mixing bowl. While still slightly warm, pour the apple cider vinegar and a pinch of additional sea salt over the potatoes and gently toss. The warm potatoes will absorb the vinegar better than cold ones, creating deeper flavor throughout. I like to add the vinegar at this stage because it seasons the potatoes from the inside out rather than just coating the surface.

While the potatoes were cooling, hard-boil the 3 eggs if not already done—place them in a separate pot of cold water, bring to a boil, remove from heat, and let sit covered for 10-12 minutes. Cool them in ice water, then peel and chop into bite-sized pieces. The extra eggs add richness and creaminess to the salad, so don't skip them!

Pour the dressing from Step 2 over the vinegar-seasoned potatoes and gently fold it in with a rubber spatula or wooden spoon, being careful not to break the potato pieces. Add the drained soaked onions, chopped celery, minced pickle, chopped eggs from Step 4, and fresh herbs to the bowl. Gently fold everything together until evenly combined and the dressing coats all ingredients. Taste and adjust seasoning with additional salt and freshly ground black pepper as needed.

Transfer the potato salad to a serving bowl and refrigerate for at least 30 minutes before serving. This allows the flavors to meld together and makes the salad more refreshing. You can make this a few hours ahead if needed—the salad actually tastes better the next day as the flavors continue to develop.