Easy Seafood Casserole Recipe

There's something magical about the smell of creamy seafood casserole bubbling in the oven—it’s rich, cozy, and reminds me of seaside dinners with family. This dish brings together tender shrimp, flaky fish, and a creamy, cheesy sauce that’s baked to golden perfection.

this Recipe

I first created this easy seafood casserole on a snowy evening when I needed something comforting but quick. It turned into an instant classic—loved for its indulgent flavor and effortless prep. Whether you're hosting guests or just craving a warm, coastal-inspired meal, this recipe is your ticket to a delicious, no-fuss dinner.

The best part? It’s ready in under an hour and uses ingredients you probably already have. Let’s dive into why this easy seafood casserole belongs in your weekly dinner rotation.

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Why You’ll Love This Easy Seafood Casserole

Get ready to meet your new weeknight hero. This Easy Seafood Casserole has everything you want in a comfort dish—rich flavor, creamy texture, and melt-in-your-mouth seafood.

It’s ridiculously simple. No need for fancy prep or exotic ingredients. This casserole is designed with busy home cooks in mind. Toss everything together, pour it into a dish, and let your oven do the work.

Perfect for any budget. You don’t need lobster tails or scallops to make a satisfying seafood meal. This recipe works beautifully with frozen or canned seafood, helping you keep costs down while still enjoying something luxurious.

Kid-approved and crowd-friendly. Despite its seafood base, this dish is surprisingly popular with picky eaters. The mild flavor, cheesy topping, and familiar casserole format win over even hesitant diners.

Make-ahead and freezer-friendly. Got a hectic week ahead? This casserole can be prepped a day in advance or frozen for later. It’s just as tasty reheated, making it ideal for meal planning.

From busy weeknights to potluck parties, this dish brings big flavor with little effort. Next, let's talk ingredients.

Ingredients Notes

The secret to this casserole’s success lies in its simplicity. Every ingredient plays a part in creating a creamy, comforting seafood bake that tastes like it came straight from a coastal bistro.

Seafood medley is the star. I usually go for a mix of shrimp, white fish (like cod or tilapia), and sometimes imitation crab. Frozen seafood works great—just be sure to thaw and pat dry before adding. Canned tuna or salmon can also be used for an extra-affordable option.

Cream of mushroom soup forms the base of the sauce. It’s a shortcut ingredient that adds creaminess and savory depth without any extra work. Cream of celery or cream of shrimp soup are great alternatives if you want to switch things up.

Mayonnaise might sound odd at first, but it’s the secret weapon here. Just a little adds richness and helps create that velvety casserole texture we all love.

Cheddar cheese, both in the mix and melted on top, brings sharpness and gooey goodness. Feel free to swap in Monterey Jack or mozzarella for a different twist, but I love the tangy bite of sharp cheddar in this dish.

Crushed buttery crackers or panko breadcrumbs add the perfect crunch on top. They soak up a little of the sauce while crisping up beautifully in the oven.

You don’t need any special equipment—just a 9x13-inch baking dish, a mixing bowl, and a spoon. That’s it!

How To Make This Easy Seafood Casserole

Creating this creamy seafood casserole is as easy as mixing, layering, and baking. Let’s walk through it together.

Start by preheating your oven to 375°F. Lightly grease your baking dish with butter or cooking spray so nothing sticks. If you're using frozen seafood, make sure it’s completely thawed and patted dry to avoid a watery casserole.

In a large bowl, mix together the cream of mushroom soup, mayonnaise, a little lemon juice, seasonings (like garlic powder, Old Bay, or paprika), and shredded cheddar cheese. This mixture forms the luscious sauce that will coat your seafood.

Fold in your seafood gently, being careful not to break up the fish too much. You want a bit of texture in every bite. Pour the entire mixture into your prepared baking dish, spreading it out evenly.

Sprinkle the top with more cheese, followed by a generous handful of crushed crackers or breadcrumbs. Drizzle lightly with melted butter to help the topping crisp up in the oven.

Bake uncovered for about 30–35 minutes, until the top is golden and bubbling at the edges. Let it sit for 5–10 minutes before serving—it’ll thicken up slightly and be easier to scoop.

From start to finish, you’re looking at under 1 hour for a truly satisfying, stick-to-your-ribs dinner.

Storage Options

This seafood casserole stores beautifully, making it perfect for leftovers or meal prepping.

If you have extras, allow the casserole to cool completely, then transfer to an airtight container. It will keep in the refrigerator for up to 3 days. For best flavor, reheat gently in the oven or microwave.

You can also freeze this dish before or after baking. To freeze before baking, assemble everything in a freezer-safe dish, cover tightly with foil and plastic wrap, and freeze for up to 2 months. Thaw in the fridge overnight before baking as directed.

If freezing leftovers, portion into individual servings and store in freezer bags or containers. Reheat straight from frozen in the microwave or bake at 350°F until hot and bubbly.

To reheat from the fridge, microwave individual portions for 1–2 minutes, or reheat the whole dish in the oven at 350°F for 15–20 minutes, covered loosely with foil.

Variations and Substitutions

One of the best things about this recipe is how flexible it is. You can mix and match ingredients based on what you have or prefer.

For a lighter version, swap the mayonnaise for Greek yogurt or light sour cream. You’ll still get creaminess, with a bit less fat and a little tang.

Add some vegetables to the mix! Chopped spinach, peas, or sautéed mushrooms blend beautifully with the seafood and add color and nutrition.

Want a more luxurious version? Toss in some scallops or use fresh crab meat. You can also splash in a bit of white wine or sherry to the sauce before baking for restaurant-quality flavor.

Don’t like cheddar? Try it with Parmesan, Swiss, or even cream cheese blended into the base.

If you need a gluten-free option, use a GF condensed soup and top with crushed gluten-free crackers or almond flour crumbs. It’s just as satisfying and suitable for more dietary needs.

No matter how you customize it, this casserole is hard to mess up. Trust your instincts, taste as you go, and make it your own!

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