Crispy Fish Sandwich Recipe with Tangy Tartar Sauce

This Fish Sandwich Recipe stacks crispy fish, creamy avocado, and a bright lemon-tart sauce on buttery toasted brioche buns. It’s packed with flavor and comes together quickly—ready in under 25 minutes.

View of the quickest Fish Sandwich, complete with bun and toppings.
chelsea

author’s note

My Filet-O-Fish–loving brother-in-law approved this one!

My brother-in-law loves the Filet-O-Fish, and I wanted to make a home version that would impress. Rather than breading and frying from scratch, I used a good frozen crispy fillet to save time without sacrificing texture. Air-frying those fillets gives excellent crispness in minutes.

Layered on buttery toasted brioche with avocado, lettuce, pickles, and a lemony tartar-style sauce, these sandwiches were the hit of the night. They’re easy, fast, and seriously tasty—perfect for busy weeknights or a quick weekend dinner.

Ingredient shot: all the elements for this Fish Sandwich recipe

Fish Sandwich Ingredients:

Ingredient Swaps & Tips
Brioche buns Potato or Hawaiian buns work well.
Frozen crispy fish fillets Any brand you like; Gorton’s is a favorite here. Air fryer crisps them quickly.
Avocado Sliced ripe avocado adds creaminess; pre-made guacamole cups can be used in a pinch.
Lettuce Butter, romaine, or shredded iceberg are great choices.
Mayo Full‑fat mayo gives the best texture and flavor for the sauce.
Lemon Use both zest and juice for the sauce.
Sweet pickle relish Finely diced bread-and-butter pickles are an easy swap.
Fresh dill Dried dill works if fresh isn’t available.
Process shots: Combine tartar sauce ingredients and mix; fry fish fillets in the air fryer.

How To Make This Fish Sandwich

  1. Make the sauce: Whisk together mayo, sweet pickle relish, chopped dill (optional), a touch of Worcestershire and Dijon-style mustard, lemon zest and juice, and salt and pepper. Chill while you prepare the rest.
  2. Cook the fish: Air fry or bake the frozen fillets according to package directions until hot and crispy.
  3. Toast the buns: Spread softened butter on the cut sides and toast on a skillet or grill until golden and slightly crisp.
  4. Assemble: Spread the sauce on both bun halves, then layer lettuce, avocado slices, the cooked fish fillet, and pickles if desired. Top with the remaining bun half.
  5. Serve immediately: Enjoy while the fillet is hot and crisp for the best texture.
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chelsea’s recipe tip

My Top Fish Sandwich Tips

  • Don’t overcrowd the fryer or oven: Give fillets room so they crisp evenly.
  • Toast the buns: It prevents sogginess and adds flavor.
  • Dry the lettuce: Wet lettuce makes the sandwich soggy fast.
  • Chill the sauce: Letting it rest melds flavors and improves taste.
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What To Serve With A Fish Sandwich

  • Fries: Sweet potato fries or crispy air‑fryer fries are great companions.
  • Coleslaw: A cool, crunchy slaw balances the warm, crispy sandwich.
  • Fruit salad: Light and refreshing for a summer meal.
  • Chips: Quick and easy for busy nights.
  • Pasta salad: Good for serving a crowd or summer dinners.
View of a hand holding a fully assembled Fish Sandwich

Storage

This sandwich is best eaten fresh while the fish is crispy. Store extra sauce in an airtight container in the fridge for 3–4 days. Reheat leftover fillets in the air fryer to help restore crispness. Avoid assembling sandwiches ahead of time to prevent sogginess.

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Fish Sandwich

By Chelsea Lords
Flaky fish, creamy avocado, and a tangy lemon sauce on buttery toasted brioche—every bite is satisfying and ready in under 25 minutes.
Prep Time: 15
Cook Time: 8
Total Time: 23
Servings: 1 sandwich

Ingredients

Sauce (makes extra)
  • 1/2 cup mayo (Best Foods/Hellman’s recommended)
  • 1 1/2 tbsp sweet pickle relish (or finely diced bread-and-butter pickles)
  • 1 tbsp finely chopped fresh dill (optional)
  • 1/2 tsp Worcestershire sauce
  • 1/2 tsp Dijon-style mustard
  • 1 lemon (use 1/2 tsp zest + 2 tbsp juice)
  • 1/8 tsp salt and 1/8 tsp pepper, or to taste
Sandwich (per serving)
  • 1 brioche bun, softened butter for toasting
  • 1 frozen crispy fish sandwich fillet
  • 1/4 large ripe avocado, thinly sliced
  • 2 pieces lettuce
  • Pickles, optional

Instructions

  • Combine all sauce ingredients in a medium bowl, using 1/2 tsp lemon zest and 2 tbsp lemon juice. Season with salt and pepper to taste. Mix well and refrigerate until ready; stir again before using.
  • Cook the frozen fish fillet according to package instructions—air fry or bake until crisp and heated through.
  • Spread softened butter on the insides of the brioche bun and toast buttered sides down in a pan over medium heat until golden, about 30–60 seconds. Watch closely to avoid burning.
  • Spread the prepared sauce on both bun halves. Layer lettuce, avocado slices, the cooked fillet, and pickles if using. Top with the other bun half and serve immediately.

Recipe Notes

Note 1: Heinz sweet relish is a solid choice, but finely diced bread-and-butter pickles work fine—aim for a consistent, small dice.

Note 2: Gorton’s fillets are recommended, but choose any crispy frozen fish you like. An air fryer speeds cooking and yields extra crispness.

Nutrition: Values vary by bun, butter, and relish choices—use listed nutrition as an estimate.

Storage: Best enjoyed fresh. Keep extra sauce refrigerated for 3–4 days and store buns at room temperature.

Nutrition

Serving: 1 serving | Calories: 622 kcal | Carbs: 33.7 g | Protein: 25 g | Fat: 44.1 g | Sodium: 1008 mg

Nutrition information is an approximation and will vary based on ingredients and portions used.

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