Trim heads of celery, cutting off top third of branches and outside stalks; cut each head in half; put celery in a saucepan with trimmings, chicken stock cube and salt; cover with cold water and bring slowly to a boil. Simmer for 10 minutes; remove from heat and leave in hot water for 5 minutes; drain and cool. Arrange celery in a flat serving dish; spoon over half of the Vinaigrette Sauce and allow celery to marinate in this mixture for at least 1 hour.
Combine remaining Vinaigrette Sauce with paprika,
To serve: place blanched celery hearts on a serving dish; cover each celery half with dressing; garnish one-third of each portion with sieved egg white, one-third with sieved egg yolk, and remaining third with finely chopped parsley. Serve immediately.