Old-Fashioned Creamy Seafood Casserole with Golden Breadcrumb Topping

This creamy seafood casserole is a comforting oven-baked dinner filled with tender shrimp, flaky white fish, and a rich homemade sauce. A buttery, herb-seasoned breadcrumb topping bakes into a beautifully golden crust, creating a delicious contrast with the creamy filling underneath.

 

Inspired by classic American family casseroles, this easy seafood bake uses familiar ingredients and a simple baking dish. It's perfect for Sunday dinners, holiday gatherings, or a cozy meal served with fresh vegetables and warm bread.

Why You'll Love This Recipe

• Rich and creamy: A homemade sauce brings the seafood together.
• Golden topping: Buttery breadcrumbs add a satisfying crunch.
• Simple preparation: Easy stovetop sauce followed by oven baking.
• Family-friendly: A comforting main dish for four to six people.
• Flexible ingredients: Works with shrimp, cod, haddock, or other firm white fish.

Recipe Information

• Prep Time: 20 minutes
• Cook Time: 30–35 minutes
• Total Time: 50–55 minutes
• Servings: 6
• Course: Main Course
• Cuisine: American-Inspired
• Method: Stovetop and Oven

Ingredients

For the Seafood Filling

• 1 pound raw shrimp, peeled and deveined
• 1 pound boneless white fish, such as cod or haddock, cut into bite-sized pieces
• 3 tablespoons unsalted butter
• 1 small yellow onion, finely diced
• 2 garlic cloves, minced
• 1/4 cup all-purpose flour
• 1 1/2 cups whole milk
• 1/2 cup low-sodium seafood or vegetable broth
• 1/2 cup heavy cream
• 1/2 cup shredded mild cheddar cheese
• 1 tablespoon fresh lemon juice
• 1 teaspoon Dijon mustard
• 1/2 teaspoon paprika
• 1/2 teaspoon dried thyme
• 1/2 teaspoon salt, or to taste
• 1/4 teaspoon black pepper
• 2 tablespoons chopped fresh parsley

For the Golden Breadcrumb Topping

• 1 cup plain breadcrumbs
• 3 tablespoons unsalted butter, melted
• 1/4 cup freshly grated Parmesan cheese
• 1/2 teaspoon dried parsley
• 1/4 teaspoon garlic powder

How to Make Creamy Seafood Casserole

Step 1: Prepare the Oven

Preheat the oven to 375°F (190°C). Lightly grease a 2-quart baking dish with butter or cooking spray.

Step 2: Prepare the Seafood

Pat the shrimp and fish dry with paper towels. Cut the fish into evenly sized pieces and keep the seafood refrigerated while preparing the sauce.

Step 3: Sauté the Aromatics

Melt 3 tablespoons butter in a large saucepan over medium heat. Add the diced onion and cook for 3–4 minutes until softened. Stir in the minced garlic and cook for another 30 seconds.

Step 4: Make the Cream Sauce

Sprinkle the flour over the onion mixture and stir continuously for 1 minute. Gradually whisk in the milk and broth until smooth.

Add the heavy cream and simmer gently for 3–5 minutes, stirring frequently, until the sauce thickens.

Step 5: Season the Sauce

Reduce the heat to low. Stir in the cheddar cheese, lemon juice, Dijon mustard, paprika, thyme, salt, and black pepper. Mix until the cheese melts and the sauce becomes smooth.

Step 6: Combine with Seafood

Remove the saucepan from the heat. Gently fold the raw shrimp, fish pieces, and fresh parsley into the warm sauce until evenly coated.

Step 7: Fill the Baking Dish

Transfer the seafood mixture into the prepared baking dish and spread into an even layer.

Step 8: Prepare the Breadcrumb Topping

In a small bowl, combine breadcrumbs, melted butter, Parmesan cheese, dried parsley, and garlic powder. Stir until the crumbs are evenly moistened.

Step 9: Add the Topping

Sprinkle the breadcrumb mixture evenly over the seafood filling, covering the surface without pressing down firmly.

Step 10: Bake Until Golden

Bake uncovered for approximately 25–35 minutes, until the filling is bubbling, the topping is golden brown, and the seafood reaches an internal temperature of 145°F (63°C).

If the topping browns too quickly, loosely cover the dish with aluminum foil.

Step 11: Rest and Serve

Remove the casserole from the oven and allow it to rest for 5 minutes. Serve warm with your favorite side dishes.

Helpful Tips for the Best Seafood Casserole

• Dry the seafood: Excess moisture can thin the creamy sauce.
• Use firm white fish: Cod and haddock hold their shape well.
• Thicken the sauce first: The filling should be creamy before baking.
• Don't overbake: Seafood can become tough with excessive cooking.
• Use a thermometer: Cook fish and shrimp to 145°F (63°C).
• Watch the topping: Cover loosely if the breadcrumbs brown before the filling is cooked.

Easy Seafood Casserole Variations

Shrimp-Only Casserole

Replace the white fish with an additional pound of raw shrimp for a shrimp-focused version.

Creamy Crab and Shrimp Bake

Replace the fish with 1 pound of picked crab meat. Check carefully for shell fragments before adding it to the filling.

Seafood and Broccoli Casserole

Add 1 cup of lightly steamed, well-drained broccoli florets to the creamy seafood mixture before baking.

Extra-Crispy Topping

Use panko breadcrumbs instead of regular breadcrumbs for a lighter, crunchier finish.

What to Serve with Seafood Casserole

• Steamed white rice
• Roasted asparagus
• Garlic green beans
• Fresh garden salad
• Buttered egg noodles
• Warm crusty bread

Storage and Reheating

Refrigerator

Transfer leftovers to shallow airtight containers and refrigerate within 2 hours. Store for up to 3 days.

Freezer

Freezing is possible, but the cream sauce may separate and the seafood texture may soften after thawing. For best quality, enjoy this casserole fresh.

Reheating

Cover the casserole and reheat at 325°F (163°C) until the center reaches 165°F (74°C). Avoid repeated reheating, which can toughen the seafood.

Frequently Asked Questions

Can I use frozen seafood?

Yes. Thaw frozen seafood completely in the refrigerator and pat dry before adding it to the casserole.

Can I make seafood casserole ahead of time?

Prepare the sauce and topping separately in advance. Refrigerate them, then combine with the seafood shortly before baking.

Why is my seafood casserole watery?

Seafood releases moisture during baking. Dry the seafood thoroughly and make sure the cream sauce is properly thickened before assembling.

Can I use canned cream soup instead?

Yes. Condensed cream of mushroom or cream of celery soup can be used as a shortcut, although the flavor and consistency will differ from homemade sauce.

What temperature should seafood casserole reach?

The seafood should reach at least 145°F (63°C). Use a food thermometer to check the thickest pieces.

Final Thoughts

This Old-Fashioned Creamy Seafood Casserole combines tender shrimp, flaky fish, rich homemade sauce, and a buttery golden topping in one satisfying baked dinner.

It's a delicious American-inspired comfort-food recipe for family meals, holiday gatherings, and cozy evenings at home.

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