Instructions

  1. Place the shrimp in a pot of boiling salted water and cook only until they begin to curl into a "c" shape; drain and place in a large bowl that has a tight-fitting lid.
  2. Combine the parsley, onion, celery, vinegars, olive oil, mustard, red pepper flakes, salt and pepper in a medium-size bowl and mix well. Pour over the shrimp.
  3. Cover the shrimp and refrigerate for at least 24 hours. Stir the mixture every several hours.
  4. Drain off the marinade and serve the shrimp in a shallow dish, accompanied by cocktail forks or toothpicks.