Step 1: Prepare the Potatoes: Place the peeled and cubed potatoes in a large pot. Cover with cold, salted water (about 1 tablespoon of salt). Bring to a boil, then reduce heat and simmer until the potatoes are tender when pierced with a fork, about 15-20 minutes. Drain thoroughly and let them cool completely in a single layer on a baking sheet or in a large bowl. This prevents them from becoming mushy.
Step 2: Prepare the Dressing: In a medium bowl, combine the mayonnaise, sour cream, mustard, apple cider vinegar, 1 teaspoon of salt, and 1 teaspoon of black pepper. Whisk until the dressing is smooth and well combined. Taste and adjust seasoning if needed.
Step 3: Assemble the Potato Salad: In a large bowl, combine the cooled potatoes, chopped celery, chopped red onion, and chopped fresh parsley. Pour the prepared dressing over the potato mixture.
Step 4: Mix and Chill: Gently fold the dressing into the potatoes and vegetables until everything is evenly coated. Be careful not to mash the potatoes. Cover the bowl and refrigerate for at least 1 hour, or preferably 4 hours, to allow the flavors to meld.
Step 5: Garnish and Serve: Before serving, give the potato salad another gentle stir. Garnish with chopped fresh chives, crumbled bacon, and a sprinkle of fresh parsley or paprika, if desired. Serve chilled and enjoy!