Meanwhile, in a medium mixing bowl, combine the mayonnaise, mustard, parsley, shallot, celery, salt, celery salt, pepper, paprika, and cayenne. Whisk until smooth. Using a fork, smash the cooled eggs in the container, then pour into the mixing bowl. Toss until combined. Serve immediately or store in an airtight container in the refrigerator for up to 3 days.