Cook the pasta in generously salted boiling water according to package instructions until al dente. Drain, rinse in cold water, and set aside to cool.

Chop four of the hard-boiled eggs into bite-sized pieces. Slice the remaining two eggs lengthwise, remove the yolks, and set the egg whites aside for garnish.

Mash the reserved egg yolks in a bowl until smooth. Add mayonnaise, sour cream or yogurt, yellow mustard, vinegar or pickle juice, paprika, salt, and black pepper. Whisk together until creamy and well blended.

In a large bowl, combine the cooled pasta, chopped eggs, diced celery, and diced red onion. Add optional chopped pickles or relish if using.

Pour the dressing over the pasta mixture and gently mix until everything is evenly coated.

Cover and refrigerate for at least 30 minutes (or up to a few hours) to allow the flavors to develop.

Before serving, arrange the reserved egg whites on top and garnish with extra paprika or fresh herbs if desired.