Homemade Filet-O-Fish Copycat Sandwich

Why You’ll Love This Recipe

• Soft, steamy bun with a delicately crisp, square fillet that feels nostalgic and fast-food perfect.
• Spot-on tangy tartar with sweet relish and capers, balanced by a gentle melt of American cheese.
• Reliable, repeatable technique: fine-crumb breading and a quick chill for that smooth, even crust.
• Clear directions for deep-fry, plus easy air-fryer and baked options.

Grocery List

• Produce: 1 small onion, 1 lemon
• Dairy: 2 slices American cheese, mayonnaise (if kept refrigerated)
• Pantry: Whitefish fillets, sweet pickle relish, capers, all-purpose flour, cornstarch, plain breadcrumbs, panko, eggs, kosher salt, white pepper, sugar, neutral frying oil, Dijon mustard (optional), paprika (optional), garlic powder (optional), hamburger buns

Full Ingredients

Fish Fillets

• 1 lb skinless whitefish (Alaska pollock, cod, or haddock), cut into four 3-inch-square, 3/4-inch-thick fillets (about 4 oz each)
• 1/2 tsp kosher salt
• 1/4 tsp white pepper
• Optional quick brine: 2 cups cold water, 2 tsp kosher salt, 1 tsp sugar

Crumb Coating

• 1/2 cup all-purpose flour
• 2 Tbsp cornstarch
• 2 large eggs
• 1 Tbsp cold water
• 3/4 cup plain dry breadcrumbs
• 1/2 cup panko, pulsed in a processor to fine crumbs
• 1/4 tsp kosher salt
• 1/4 tsp paprika (optional, for color)
• 1/4 tsp garlic powder (optional, very light flavor)

For Frying

• Neutral oil (canola, peanut, or vegetable) for deep frying, about 1.5 quarts to reach 1.5 inches depth

Tartar Sauce

• 1/2 cup mayonnaise
• 2 Tbsp sweet pickle relish
• 1 Tbsp very finely minced onion
• 1 tsp capers, minced
• 2 tsp fresh lemon juice
• 1/2 tsp sugar
• 1/4 tsp Dijon mustard (optional)
• Pinch kosher salt, to taste

Buns and Assembly

• 4 soft hamburger buns
• 2 slices American cheese, each cut in half (you will use half a slice per sandwich)
• 1–1.5 Tbsp tartar sauce per sandwich

Step-by-Step Instructions

Step 1: Portion and optionally brine the fish

Trim the fish into four neat, 3-inch-square fillets about 3/4 inch thick. If any piece is thin at an edge, tuck it underneath to square it off. For extra juiciness and mild seasoning, stir 2 tsp kosher salt and 1 tsp sugar into 2 cups cold water, submerge the fish for 10 minutes, then drain and pat completely dry. Season both sides with 1/2 tsp kosher salt and 1/4 tsp white pepper.

Step 2: Stir together the tartar sauce

In a small bowl, mix mayonnaise, sweet pickle relish, minced onion, capers, lemon juice, sugar, Dijon (if using), and a pinch of salt. Taste and adjust salt or lemon. Cover and refrigerate at least 15 minutes to meld flavors while you bread and fry the fish.

Step 3: Set up the breading station

Put flour and cornstarch in a shallow dish. In a second dish, whisk the eggs with 1 Tbsp cold water. In a third dish, combine the plain breadcrumbs, the finely pulsed panko, 1/4 tsp kosher salt, and optional paprika/garlic powder. The fine crumb mix is key to a smooth, even coating that fries up evenly.

Step 4: Bread the fish and square the edges

Dredge each fillet in the flour mixture, shaking off excess. Dip into the egg wash, letting excess drip, then press all sides firmly into the crumb mixture, paying extra attention to the edges to keep the fillets square. For an extra-smooth, thicker crust, repeat the egg and crumb steps for a double coat.

Step 5: Chill to set the coating

Transfer breaded fillets to a parchment-lined sheet and refrigerate 20–30 minutes (or freeze 10–15 minutes). This helps the crumbs adhere so they do not shed in the oil and ensures a smooth, uniform crust.

Step 6: Fry until golden and tender

Pour oil into a deep, heavy pot to 1.5 inches depth. Heat to 350°F, monitoring with a thermometer. Fry 2 fillets at a time for 4–5 minutes total, turning once if needed, until deeply golden and the centers reach 150°F. Drain on a wire rack and lightly sprinkle with a pinch of salt. Return oil to 350°F before frying the next batch.

Step 7: Steam buns and assemble

Bring 1 inch of water to a simmer in a pot fitted with a steamer basket. Add the buns (split), cover, and steam 30–45 seconds until warm and pillowy. Quickly wipe any condensation from the cut sides. To build each sandwich, place a half-slice of American cheese on the bottom bun, top with a hot fish fillet, spread 1–1.5 Tbsp tartar sauce on the top bun, and close. Serve immediately while the bun is steamy and the cheese is gently melting beneath the fish.

Pro Tips

• Pulse panko to a fine crumb for that signature, uniform crust; coarse crumbs look pebbly.
• Chilling the breaded fillets is non-negotiable for clean edges and minimal crumb loss in the oil.
• Keep oil at 350°F; too cool equals greasy crust, too hot burns before the center cooks.
• Steam buns right before assembly to keep them soft and squishy—avoid over-steaming or they will get soggy.
• Cheese under the fish mimics the original and melts just enough from the fillet’s heat.

Variations

• Air-Fryer: Spray breaded fillets lightly with oil and cook at 400°F for 10–12 minutes, flipping at 7 minutes, until golden and 150°F inside.
• Oven-Baked: Arrange on a rack set over a sheet pan, mist with oil, and bake at 425°F for 14–16 minutes.
• Spicy Twist: Add 1/4 tsp cayenne to crumbs and stir 1 tsp hot sauce into the tartar for gentle heat.

Storage & Make-Ahead

Tartar sauce can be made up to 5 days in advance and refrigerated. Breaded, uncooked fillets can be frozen on a sheet until firm, then stored airtight for up to 1 month; fry from frozen at 350°F for 6–7 minutes. Leftover cooked fillets re-crisp at 400°F for 8–10 minutes. Buns are best steamed to order; avoid storing assembled sandwiches, as the bun softens and the crust loses crispness.

Nutrition (per serving)

Approximate per sandwich: 500 calories; 24 g protein; 45 g carbohydrates; 24 g fat; 6 g saturated fat; 1 g fiber; 9 g sugar; 900–1000 mg sodium. Values will vary with oil absorption and bun brand.