- 1 clove garlic, minced
- 1 medium rib celery, finely chopped
- 2 tablespoons chopped fresh Italian (flat-leaf) parsley
- ¼ cup thinly sliced scallions (white and green parts, about 2 scallions)
- 2 tablespoons white-wine vinegar
- 1 tablespoon paprika
- 1/8 teaspoon kosher salt
- 1½ teaspoons prepared horseradish
- ¼ cup Creole or stone-ground mustard
- 1 tablespoon ketchup
- 1½ teaspoons Tabasco sauce
- ½ cup olive oil
- 1 large carrot, peeled and sliced
- 1 medium onion, sliced
- 1 rib celery, sliced
- 1 bay leaf
- 2 tablespoons kosher salt
- 1 tablespoon black peppercorns
- 2 tablespoons lemon juice (about 1 lemon)
- 5 cups cold water
- 1 pound extra-large shrimp, unpeeled (Love Note 1)
- 1 cup shredded iceberg lettuce
- 1 bunch scallions, thinly sliced diagonally (white and green parts, ends trimmed)
- To make the Rémoulade Sauce:
- Place the garlic, celery, parsley, scallions, vinegar, paprika, salt, horseradish, mustard, ketchup, and hot sauce in a blender or the bowl of a small food processor fitted with the metal blade. Blend until combined.
- With the machine running, add the oil in a slow, steady stream. Continue processing until the oil is incorporated and emulsified, giving the sauce a thick, creamy consistency. Taste and add more salt, if necessary.
- Using a rubber spatula, scrape the sauce into an airtight container and chill for at least 30 minutes before serving, preferably a few hours or overnight. (This helps meld the flavors and mellow out the scallions.) The sauce can be made up to 3 days ahead and stored, tightly covered, in the refrigerator.
- To make the shrimp:
- Place the carrots, onions, celery, bay leaf, salt, peppercorns, lemon juice, and water in a large saucepan. Bring to a boil over high heat, reduce the heat, and simmer, uncovered, for 15 minutes. Meanwhile, prepare an ice bath with 4 cups of ice cubes and 4 cups of cold water in a large bowl.
- Turn off the heat, add the shrimp, cover the pot, and let sit for 5 to 6 minutes (stirring the shrimp once or twice to make sure they all get submerged in the water), or until they are white all the way through (peel one to check).
- Strain the shrimp through a sieve set over a bowl and place in the ice bath to cool for about 1 minute before peeling. Reserve the cooking liquid to make shrimp stock, if desired (Love Note 2).
- Peel the shrimp and devein them (Love Note 3), keeping the tails intact (they look more appetizing that way).
- Place the shrimp in a large bowl. Add about 1/3 cup of the rémoulade and gently toss to generously coat the shrimp. Allow the shrimp to marinate in the sauce for 20 minutes.
- To serve:
- Place a thin layer of lettuce on each plate. Arrange the shrimp on top of the lettuce, allowing 4 or 5 per serving. Top with the scallions and serve.