Easy Seafood Casserole Recipe

There's something magical about a bubbling seafood casserole coming out of the oven, filling your kitchen with the scent of garlic, butter, and ocean-fresh goodness. With tender shrimp, flaky fish, and a golden breadcrumb topping, this Easy Seafood Casserole is as comforting as it is impressive.

this Recipe

I first made this dish after a beach vacation when I came home with a cooler full of fresh seafood and zero energy to do anything complicated. One dish, one pan, and dinner was served – rich, creamy, and devoured in minutes.

This recipe has become my go-to for casual dinner parties or weeknights when I want something a little special without the hassle. It’s quick, simple, and oh-so-satisfying.

Let me show you why this will become your new favorite weeknight dinner.

Why You'll Love This Easy Seafood Casserole

Get ready to fall head over heels for this creamy, dreamy casserole. Whether you're a seasoned seafood lover or testing the waters, this recipe makes it easy to dive in.

It’s shockingly easy to make. You don’t need to be a chef or live near the coast to pull this off. It uses easy-to-find frozen seafood and pantry staples – no fancy ingredients or equipment required.

Dinner in under an hour. From prep to plate, you can have this casserole on the table in just about 45 minutes. That includes chopping, mixing, baking, and even a few minutes to sneak a glass of wine.

Feeds a crowd – or gives you leftovers. This dish makes 4-6 hearty servings, so it’s perfect for families or for meal prepping ahead. It reheats beautifully and may even taste better the next day.

It’s comfort food with a twist. The creamy, cheesy sauce is indulgent without being heavy, and the crispy topping adds the perfect crunch. Plus, the seafood keeps it light and fresh.

Once you try it, you’ll see why this recipe is requested over and over in my house.

Ingredients Notes

The beauty of this Easy Seafood Casserole is how flexible and forgiving the ingredients are. You can tailor it to your taste or what’s in your freezer – and it still comes out delicious every time.

Seafood mix is the star. I typically use a frozen seafood medley that includes shrimp, scallops, and crab or white fish. You can find these blends in most grocery store freezer sections. Just be sure to thaw and pat dry before adding to the dish to prevent excess moisture.

The creamy base is pure comfort. A combination of cream of mushroom soup and sour cream creates the creamy foundation for the casserole. It’s rich, tangy, and coats the seafood perfectly without overpowering it.

Cheddar cheese adds that melty magic. A generous handful of shredded sharp cheddar melts into the sauce as it bakes, adding depth and a hint of sharpness that balances out the creaminess.

Seasoned breadcrumbs bring the crunch. Topping the casserole with buttery breadcrumbs gives it a golden, crispy finish. I like to mix them with a little Parmesan cheese and melted butter before sprinkling on top for extra flavor.

Optional extras make it yours. A handful of chopped parsley, a squeeze of lemon juice, or a dash of Old Bay seasoning can all elevate the flavor. I always keep lemon on hand to brighten up the final dish.

No special tools are required – just a mixing bowl, a 9x13-inch baking dish, and an oven. A rubber spatula helps with mixing and spreading the creamy filling evenly.

How To Make This Easy Seafood Casserole

Making this casserole couldn’t be easier, and it all comes together in one dish. Here’s how to pull it off like a pro.

Start by preheating your oven to 375°F. While the oven heats, thaw your seafood if it’s frozen. Rinse it gently under cold water and pat dry with paper towels to remove any excess moisture that might make the casserole watery.

In a large bowl, combine your seafood, cream of mushroom soup, sour cream, and shredded cheddar. Add a touch of salt, pepper, and garlic powder for seasoning. Give it all a good mix until everything is evenly coated. Don’t be afraid to add a little extra cheese if you’re feeling indulgent!

Next, transfer the mixture into a greased baking dish, smoothing it out into an even layer. The seafood will release a bit of liquid as it cooks, so you don’t want to overfill the pan.

Now it’s time for the topping. In a small bowl, mix together seasoned breadcrumbs, Parmesan cheese, and melted butter until it looks like wet sand. Sprinkle this generously over the top of the casserole. This is what creates that irresistible golden crust.

Bake uncovered for 30–35 minutes, until the top is golden brown and the sides are bubbling. Keep an eye on it in the last few minutes – if the top is browning too fast, you can loosely tent it with foil.

Once out of the oven, let it rest for 5 minutes before serving. This helps everything set and makes it easier to scoop.

Storage Options

This casserole keeps incredibly well, making it ideal for leftovers or meal prep.

In the fridge, store leftovers in an airtight container for up to 3 days. The flavors meld beautifully overnight, and the casserole maintains its texture surprisingly well.

To freeze, let the casserole cool completely before transferring to a freezer-safe container. I recommend freezing before baking if you’re prepping ahead – simply assemble everything, wrap tightly with foil, and freeze for up to 2 months.

When reheating, use the oven or air fryer for best results. Microwave works in a pinch, but it may soften the topping. To re-crisp, bake at 350°F for about 15–20 minutes or until heated through and bubbly.

Variations and Substitutions

This recipe is incredibly versatile, which means you can make it your own based on your taste or what you have on hand.

Swap in your favorite seafood. Don’t love scallops? Use more shrimp. Can’t find a seafood mix? Try using just cod or salmon. As long as the seafood is cooked or quick-cooking, it’ll work beautifully here.

Use a different creamy base. Not a fan of mushroom soup? Cream of celery, cream of shrimp, or even a homemade white sauce can step in. Greek yogurt can sub in for sour cream if you're watching calories.

Make it gluten-free. Swap in gluten-free breadcrumbs and double-check your soup base is certified gluten-free. The rest of the dish is naturally GF!

Add some veggies. Frozen peas, chopped spinach, or sautéed mushrooms can add color and nutrition. Just make sure they’re not too watery before adding.

Spice it up. A sprinkle of Cajun seasoning, a pinch of red pepper flakes, or even a dash of hot sauce can add a little kick if you like heat.

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