Classic Creole Shrimp Rémoulade

• 1 egg yolk
• 1/4 cup Creole mustard (preferably Zatarain’s brand) or other whole-grain spicy mustard
• 2 1/2 tablespoons red wine vinegar
• 1 tablespoon prepared horseradish
• 1 teaspoon kosher salt
• 1 teaspoon paprika
• 1/2 teaspoon cayenne
• 1/4 teaspoon freshly ground black pepper
• 1 clove garlic, minced
• 3/4 cup vegetable oil
• 1/4 cup olive oil
• 1/2 cup finely minced celery
• 1/4 cup plus 2 tablespoons minced green onions (white and green parts)
• 1/4 cup mayonnaise
• 1 tablespoon ketchup
• 1/4 teaspoon Worcestershire sauce

• 1 large onion, peeled and halved
• 1/4 cup kosher salt
• 2 tablespoons freshly squeezed lemon juice
• 1 1/2 teaspoons liquid crab boil (preferably Zatarain’s brand)
• 1 1/2 pounds large gulf shrimp, peeled and deveined
• Rémoulade as needed
• Finely sliced fresh chives for garnish (optional)

To make the rémoulade, whisk together the egg yolk, mustard, vinegar, horseradish, 3/4 teaspoon of the kosher salt, paprika, cayenne, and black pepper in a nonreactive mixing bowl. On a cutting board, mash the garlic to a paste with the remaining 1/4 teaspoon kosher salt using the side of a chef’s knife. Add the garlic paste to the bowl and whisk to combine.

Combine the oils in a measuring cup with a pour spout and, while whisking vigorously, drizzle the oil blend very slowly into the mustard mixture until a smooth, thick emulsion forms. Whisk in the celery, green onions, mayonnaise, ketchup, and Worcestershire sauce. Chill thoroughly before using, up to 2 days in advance.

To make the shrimp, fill a large saucepan two-thirds full with water and add the onion halves. Bring to a boil over medium-high heat.

While waiting for the water to come to a boil, fill a large bowl with 1 quart of cool water. Add the salt, lemon juice, and liquid crab boil. Stir to dissolve the salt. Add 2 quarts of ice and set the seasoned ice bath aside.

When the water comes to a boil, add the shrimp and cook for 2 minutes. Immediately remove from the heat and allow the shrimp to sit in the hot water until just cooked through, about 1 minute longer. Drain the shrimp promptly and transfer them to the ice bath; chill until completely cool. Drain the shrimp in a colander and pat them dry. Refrigerate until ready to serve.

When ready to serve, toss the shrimp with a generous amount of the rémoulade―it should thoroughly coat the shrimp. (Save any remaining rémoulade for another purpose.) Serve the shrimp rémoulade in chilled bowls, garnished with a sprinkling of chives if desired.