Broiled Bluefish with Mustard-Crumb Crust

Why You’ll Love This Recipe

• Bold, clean flavors: tangy Dijon, bright lemon, and fresh thyme complement bluefish’s rich, meaty character.
• Fast weeknight-friendly technique: quick roast for doneness, quick broil for an ultra-toasty crumb.
• Buttery cracker crust delivers big crunch without fuss—no deep frying needed.
• Fresh cucumber-dill salad keeps the plate light and balanced.

Grocery List

• Produce: 1 English cucumber, 1/4 small red onion, 1 lemon, fresh dill, fresh thyme, 1 garlic clove, fresh parsley
• Dairy: Unsalted butter
• Pantry: Bluefish fillets, Dijon mustard, mayonnaise, buttery crackers (e.g., Ritz), extra-virgin olive oil, paprika or cayenne, kosher salt, black pepper, sugar

Full Ingredients

Bluefish with Mustard Layer

• 1 1/2 pounds bluefish fillets, preferably skin-on, cut into 4 portions
• 3 tablespoons Dijon mustard
• 1 tablespoon mayonnaise
• 1 teaspoon finely grated lemon zest
• 1 tablespoon fresh lemon juice
• 1 teaspoon fresh thyme leaves, chopped (or 1/2 teaspoon dried thyme)
• 1 small garlic clove, finely grated or minced
• 1/4 teaspoon kosher salt, plus more to season fish
• Freshly ground black pepper

Buttery Cracker Crumb Topping

• 1 cup finely crushed buttery crackers (about 24 crackers)
• 2 tablespoons unsalted butter, melted and slightly cooled
• 1 tablespoon extra-virgin olive oil
• 1 tablespoon chopped fresh parsley
• 1/4 teaspoon sweet paprika (or a pinch of cayenne for heat)
• Pinch kosher salt (taste first; many crackers are salty)

Cucumber-Dill Salad

• 1 English cucumber, thinly sliced
• 1/4 small red onion, very thinly sliced
• 2 tablespoons chopped fresh dill
• 1 tablespoon fresh lemon juice
• 2 teaspoons extra-virgin olive oil
• 1/4 teaspoon sugar
• Kosher salt and black pepper, to taste

To Serve

• Lemon wedges
• Extra dill or parsley (optional)

Step-by-Step Instructions

Step 1: Preheat and prepare the pan

Set a rack in the middle position and another 6 inches from the broiler element. Heat the oven to 450°F. Line a rimmed sheet pan with foil for easy cleanup and brush or spray the foil lightly with olive oil.

Step 2: Make the mustard–thyme layer

In a small bowl, combine the Dijon, mayonnaise, lemon zest, lemon juice, thyme, garlic, 1/4 teaspoon kosher salt, and several grinds of black pepper. Stir until smooth. This thin, tangy paste helps season the fish and gives the crumbs something to cling to.

Step 3: Mix the buttery cracker crumbs

In a medium bowl, mix the crushed buttery crackers with the melted butter, olive oil, parsley, paprika (or cayenne), and a small pinch of salt if needed. Toss until every crumb looks glossy and evenly moistened; this ensures thorough browning under high heat.

Step 4: Season and cap the fish

Pat the bluefish fillets dry with paper towels and check for pin bones, removing any you find. Lightly season the fish with salt and pepper. Spread the mustard mixture evenly over the top of each fillet. Spoon the crumb mixture on top, pressing gently to form a cohesive, even cap that reaches the edges.

Step 5: Roast hot until nearly done

Place the fish on the prepared sheet, skin-side down. Roast on the middle rack at 450°F for 7 to 9 minutes for 1-inch-thick fillets (a bit less for thinner pieces), until the fish is just turning opaque and flakes at the edges but is not fully browned on top.

Step 6: Broil to toast the crust

Switch the oven to broil on high and move the pan to the top rack (about 6 inches from the element). Broil for 1 to 3 minutes, watching closely, until the cracker crumbs are deeply golden and the edges of the fish sizzle. The internal temperature should reach 130–135°F. Let rest 2 minutes on the pan.

Step 7: Toss the cucumber–dill salad and serve

While the fish roasts (or while it rests), combine the cucumber, red onion, dill, lemon juice, olive oil, sugar, and a pinch each of salt and pepper in a bowl. Toss and let stand 5 minutes to lightly soften. Plate the fish with a heap of salad and serve with lemon wedges and extra herbs if you like.

Pro Tips

• Buy very fresh bluefish and cook it the day you purchase it; its rich flesh is best when ultra-fresh.
• Crush crackers to fine, even crumbs for a cohesive crust that browns uniformly and doesn’t shed.
• Balance doneness and browning by roasting first, then broiling—this prevents burnt crumbs with undercooked fish.
• Aim for 130–135°F internal temp for moist, flaky results; carryover heat finishes the job.
• Keep the skin on: it protects the flesh from the hot pan and peels off easily after cooking if desired.

Variations

• Swap the fish: Salmon, mackerel, or haddock also work. Adjust time for thickness (salmon may need 2–3 extra minutes before broiling).
• Herb and mustard twist: Use tarragon or chives, and replace half the Dijon with whole-grain mustard or a touch of horseradish.
• Gluten-free or dairy-free: Use gluten-free buttery-style crackers; replace butter with all olive oil.

Storage & Make-Ahead

The crumb mixture and mustard spread can be made 1 day ahead; cover and refrigerate. Assemble right before cooking. Leftover fish is best within 1 day; store in an airtight container in the refrigerator. Reheat at 350°F for 8–10 minutes, then broil briefly to re-crisp the crumbs. The cucumber salad is best fresh; if making ahead, slice and salt the cucumber for 15 minutes, drain, then dress just before serving to avoid excess liquid.

Nutrition (per serving)

Approximate values: 490 calories; 28 g fat; 17 g carbohydrates; 33 g protein; 2 g fiber; 740 mg sodium. Values will vary based on exact brands and cracker type.