Grilled Fish Sandwich With Slaw & Tzatziki

This grilled fish sandwich hits all the right notes—crispy edges, juicy inside, and full of fresh, bold flavor.

The fish is grilled with lemon and spices that give it just enough kick without overwhelming the other layers.

Tucked inside a toasted bun, it’s stacked with cool spinach, crunchy red cabbage, and a thick layer of tangy homemade tzatziki that soaks into every bite.

You can prep the sauce and slaw while the fish sits in the marinade. It all moves quickly from there, and before you know it, everything’s ready to build.

The slaw softens just enough to work with the sauce, and if you’re into big flavor without heavy toppings, this one nails it.

Great for backyard meals, casual dinners, or when you’re in the mood for something grilled that doesn’t taste like the usual.

Table of Contents

Grilled Fish Sandwich With Slaw & Tzatziki Recipe

Ingredients

For The Fish

2 fresh white fish fillets (tilapia, cod, or haddock), about 4 oz each
1 tablespoon olive oil
1 teaspoon lemon juice
1/2 teaspoon garlic powder
1/2 teaspoon onion powder
1/2 teaspoon paprika
1/4 teaspoon dried oregano
Salt and black pepper to taste

For The Slaw

1 cup shredded red cabbage
1 teaspoon apple cider vinegar
1 teaspoon lemon juice
1/2 teaspoon sugar
Pinch of salt

For The Tzatziki Sauce

1/2 cup thick plain yogurt (Greek-style preferred)
1/4 cup finely grated cucumber (peeled and squeezed to remove moisture)
1 tablespoon finely chopped fresh dill
1 small garlic clove, minced
1 teaspoon lemon juice
Salt and pepper to taste

For Assembling

2 brioche burger buns (lightly toasted)
1/2 cup fresh baby spinach or butter lettuce
Extra tzatziki sauce for spreading

Instructions

Pat the fish fillets dry with a paper towel. In a small bowl, mix olive oil, lemon juice, garlic powder, onion powder, paprika, oregano, salt, and pepper. Rub this mixture evenly onto both sides of the fish. Let it marinate for 10–15 minutes at room temperature.
Heat a non-stick grill pan or outdoor grill over medium-high heat. Lightly oil the surface. Place the fish fillets on the hot grill and cook for about 3–4 minutes per side, or until the fish is opaque and has grill marks. Be gentle when flipping to avoid breaking the fillets. Remove and let them rest for a minute.
In a bowl, combine shredded red cabbage, apple cider vinegar, lemon juice, sugar, and a pinch of salt. Toss well to coat and set aside for 5–10 minutes to allow the flavors to blend and cabbage to soften slightly.
In a small bowl, mix yogurt, grated cucumber, dill, minced garlic, lemon juice, salt, and pepper. Stir until smooth and creamy. Chill it in the fridge until ready to use.
Lightly toast the burger buns in a dry skillet or on the grill for about 1 minute until golden brown.
Spread a generous layer of tzatziki sauce on the bottom bun. Add a few baby spinach or lettuce leaves, then layer one grilled fish fillet. Top with a spoonful of cabbage slaw, then stack the second fillet on top. Add more spinach and a final drizzle of tzatziki. Finish with the top bun.
Press down gently to help hold the layers together. Serve right away with lemon water or your favorite side.

How Do I Stop The Fish From Falling Apart While Grilling?

Fish can be delicate, especially white fish fillets, so handling it properly is important for a good sandwich result.

Choose Firm Fish: Use fillets like cod, halibut, or haddock that hold together better when grilled. Flaky fish like tilapia or sole can break more easily.
Dry The Fish First: Pat the fillets dry with paper towels before seasoning. This helps them sear better and keeps the surface from steaming.
Oil The Fish, Not Just The Grill: Lightly coat both sides of the fish with olive oil before grilling. This helps prevent sticking.
Preheat The Grill Properly: Make sure your grill or grill pan is hot before placing the fish. A hot surface will sear the outside quickly and help keep the shape.
Don’t Move It Too Soon: Let the fish cook undisturbed for a few minutes before flipping. It naturally releases when it’s ready to turn.
Use A Wide Spatula: A fish spatula or a wide flat turner gives better support during flipping and reduces tearing.

Can I Use A Different Type Of Fish For This Sandwich?

You’re not limited to just one type of fish—many white fish options work well here as long as they’re firm and mild.

Halibut: Thick, meaty, and holds up beautifully on the grill.
Snapper: Mild in flavor with a firm texture that works well for sandwiches.
Grouper: A little richer in taste but still firm and great for grilling.
Mahi Mahi: Slightly sweet, holds shape well, and is often used in grilled sandwiches.
Barramundi: A clean-tasting fish that sears well and gives a buttery texture.

What’s The Best Way To Keep The Bun From Getting Soggy?

No one likes a soggy sandwich bun, especially when you’ve taken time to grill the fish just right. Here’s how to avoid that:

Toast The Buns: Lightly toasting the inside of the buns adds a barrier that helps keep sauces and slaw from soaking in.
Layer Wisely: Start with greens like spinach or lettuce on the bottom. They act as a shield between the bun and any moisture.
Drain The Slaw: Make sure the cabbage slaw isn’t too wet before assembling the sandwich. Letting it sit for a few minutes after mixing helps release excess moisture.
Use A Thick Sauce: A creamy, thick tzatziki won’t run as much as a thin sauce would, so the bun stays dry and holds together.

Can I Make The Tzatziki Sauce In Advance?

Yes, and it actually gets better after a little rest in the fridge. Preparing it ahead makes the sandwich faster to assemble too.

Flavor Develops Over Time: Letting the sauce chill for a few hours helps the garlic, lemon, and herbs blend more deeply into the yogurt.
Store In An Airtight Container: It will stay fresh for up to 3–4 days in the refrigerator.
Keep It Cold: Don’t leave it out too long. Only take out what you need when assembling the sandwich.
Stir Before Using: The sauce may separate slightly, so give it a quick stir to mix it back together before spreading.

How Do I Store Leftover Grilled Fish Sandwich Components?

Storing each part properly helps keep everything fresh and safe to eat the next day.

Grilled Fish: Store cooled fish fillets in an airtight container in the refrigerator. Eat within 2 days. Reheat gently in a skillet or microwave to keep the texture.
Slaw: Keep the slaw in a separate sealed container. It stays crisp for about 2–3 days, though the color may bleed slightly.
Tzatziki Sauce: Refrigerate in a closed container and use within 3–4 days. Stir before each use.
Buns: Store at room temperature in a sealed bag for up to 2 days. If you’ve already toasted them, a quick warm-up in a pan or toaster helps freshen them up.

Can I Make This Sandwich Ahead For Meal Prep?

You can prep many parts ahead of time, but it’s best to assemble the sandwich right before eating so it doesn’t get soggy.

Make The Tzatziki A Day Ahead: This actually helps the flavor improve overnight.
Grill And Store The Fish: You can cook the fish in advance and store it in the fridge. Reheat gently when you’re ready to assemble.
Keep The Slaw In A Container: Pre-mixed slaw keeps well and stays crunchy if you drain off excess liquid before storing.
Toast Buns Just Before Serving: This keeps them fresh and gives a better texture when you build the sandwich.

Can I Use Store-Bought Tzatziki Instead Of Homemade?

If you’re in a hurry or don’t have all the ingredients, store-bought tzatziki is a solid substitute that still works well in this sandwich.

Choose A Thick One: Go for a version that’s creamy and not too runny so it doesn’t soak into the bun too fast.
Look For Fresh Ingredients: Some brands use fresh garlic, cucumber, and dill, which helps match the homemade flavor closely.
Check The Flavor: Some store-bought versions are tangier than others. You can adjust the sandwich by adding a bit of lemon or a pinch of salt if needed.
Great For Shortcuts: It saves time and effort without compromising much on taste or texture.

What’s A Good Side Dish To Serve With This Sandwich?

The sandwich is hearty on its own, but pairing it with something light and refreshing keeps the meal balanced.

Lemon Herb Potato Wedges: Crispy roasted potatoes with a squeeze of lemon add brightness and crunch.
Cucumber Salad: Thinly sliced cucumbers tossed with vinegar and a bit of dill offer a cool, fresh contrast.
Sweet Potato Fries: These add color and a slightly sweet flavor that pairs nicely with the spiced fish.
Watermelon Cubes Or Fruit Salad: A fresh, juicy fruit option keeps the meal from feeling too heavy.

How Can I Reheat The Fish Without Drying It Out?

Reheating grilled fish can be tricky, but doing it gently helps keep the moisture inside.

Use A Skillet: Heat a pan over low to medium heat with a splash of olive oil. Warm the fish for a few minutes on each side until heated through.
Cover It While Heating: This traps steam and keeps the fish from drying out.
Avoid High Heat: Don’t blast it in a hot pan or microwave. That can make the fish rubbery.
Microwave Option: If you use a microwave, place the fish on a plate, cover with a damp paper towel, and heat for about 30 seconds at a time until warm.