Chop six hard-boiled eggs; set aside. Slice remaining hard-boiled eggs and refrigerate. In a large serving bowl, combine the chopped eggs, potatoes, celery, olives, parsley, salt and pepper; refrigerate.
For dressing, combine the sugar, flour, salt and mustard in a saucepan. Combine the egg yolks, vinegar and water; gradually whisk into saucepan. Add butter. Bring to a boil, stirring constantly. Cook and stir for 1-2 minutes or until thickened. Cool to room temperature, stirring several times. Pour over potato mixture; gently stir to coat. Cover and refrigerate for at least 2 hours. Top with sliced eggs; sprinkle with paprika.