Blackened Fish Sandwiches with Horseradish Tartar Sauce


Fresh fillets of haddock are coated with smoky paprika, garlic powder, oregano, and thyme before they get a quick sear to develop a delicious crust. They are then sandwiched between toasted brioche buns smeared with a strong, tangy tartar sauce laced with refreshingly piquant horseradish. If your fish fillets are thicker than 3/4 inch, butterfly them by carefully cutting through the center of the fillet (parallel to the work surface), leaving 1/2 inch of the meat attached at the side so it can be opened like a book.

Total Time:
20 mins


Tartar Sauce

  • ¼ cup mayonnaise

  • ¼ cup sour cream

  • 3 tablespoons minced shallot (from 1 medium shallot)

  • 2 tablespoons minced fresh flat-leaf parsley

  • 1 ½ tablespoons drained prepared horseradish

  • 1 ½ tablespoons  fresh lemon juice

  • 1 ½ tablespoons minced cornichons (about 4 small cornichons)

  • 1 tablespoon drained capers, chopped

  • ¼ teaspoon kosher salt

  • ¼ teaspoon black pepper


  • 1 teaspoon hot paprika

  • 1 teaspoon garlic powder

  • 1 teaspoon minced fresh oregano

  • 1 teaspoon minced fresh thyme

  • 1 teaspoon kosher salt

  • ½ teaspoon black pepper

  • 4 (4- to 5-ounce) skinless haddock fillets (about 3/4 inch thick)

  • ¼ cup plus 2 teaspoons unsalted butter, divided

  • 4 brioche hamburger buns, split

  • 1 tablespoon  canola oil

  • Butter lettuce leaves, for serving


Make the tartar sauce:

  1. Whisk together mayonnaise, sour cream, shallot, parsley, horseradish, lemon juice, cornichons, capers, salt, and pepper in a small bowl. Refrigerate until ready to use.

Make the sandwiches:

  1. Stir together paprika, garlic powder, oregano, thyme, salt, and pepper in a small bowl. Sprinkle spice mixture evenly over both sides of fish fillets. Set aside.

  2. Heat a large cast-iron skillet over high. Spread 1 teaspoon butter over cut side of each bun half. Place buns, buttered side down, in hot skillet; cook until well toasted and browned, about 1 minute. Transfer to a work surface. Do not wipe skillet clean.

  3. Add oil and remaining 2 tablespoons butter to skillet; cook over high until butter is melted. Add fish fillets; cook until blackened on bottoms, about 3 minutes. Flip fillets; cook until blackened on other sides and just cooked through, 2 to 3 minutes. Remove from heat, and transfer fish to a plate.

  4. Spread 1 tablespoon tartar sauce over toasted side of each bun half. Arrange fish and lettuce evenly on bottom bun halves. Cover with top bun halves, toasted side down. Serve alongside remaining 1/2 cup tartar sauce at the table.

    Blackened Fish Sandwiches with Horseradish Tartar Sauce
    Photo by Victor Protasio / Food Styling by Margaret Monroe Dickey / Prop Styling by Audrey Davis

Suggested Pairing

Lightly spicy Rhône-style white: Tablas Creek Vineyard Côtes de Tablas Blanc

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