Creamy Seafood Casserole

Lump crabmeat and shrimp in an Old Bay cream sauce, baked under cheddar and breadcrumbs until the top is golden and the edges are bubbling. This is a casserole that works for a weeknight dinner and doubles as the kind of thing you bring to a holiday table without apologizing for it.

One thing to know before you start: add the shrimp raw, not pre-cooked. Raw shrimp folded into the sauce finishes cooking perfectly during the 25 to 30 minute bake. Pre-cooked shrimp — which looks like the safer choice — turns rubbery by the time the casserole comes out of the oven. Raw in, right texture out.

Prep: 20 minutes  ·  Bake: 25–30 minutes  ·  Serves 8

What You Need

The vegetables:

• 1 cup yellow onion, finely chopped
• 1 cup bell pepper, finely chopped — green or red
• 1 cup celery, finely chopped
• 2 cloves garlic, minced
• ¼ cup (60g) unsalted butter

The cream sauce:

• ¼ cup (30g) all-purpose flour
• 2 cups (480ml) whole milk
• 1 cup (240ml) chicken broth
• 1 teaspoon Old Bay seasoning
• Salt and black pepper to taste

The seafood:

• 1 lb (450g) lump crabmeat, picked over for shells
• 1 lb (450g) raw shrimp, peeled and deveined — medium or large

The topping:

• 1 cup shredded cheddar cheese
• 1 cup breadcrumbs — panko gives a crispier top than regular breadcrumbs
• Fresh parsley, chopped, for garnish

this now & bake later ❤️

How to Make It

Start with the Vegetables

Preheat the oven to 375°F (190°C). Grease a 9×13-inch baking dish and set it aside.

Melt the butter in a large skillet over medium heat. Add the onion, bell pepper, celery, and garlic and cook, stirring occasionally, until completely softened — about 5 to 7 minutes. Don’t rush this. Soft, translucent vegetables build the flavor base the sauce sits on.

Make the Cream Sauce

Stir the flour into the softened vegetables and cook for 2 full minutes, stirring constantly. The flour needs to cook out — you’ll notice the mixture starts to smell faintly nutty and less raw as it cooks. This step prevents a floury taste in the finished sauce.

Gradually whisk in the milk, adding it in a slow stream while whisking. Then whisk in the chicken broth. Keep whisking — continuous motion is what prevents lumps from forming. Cook over medium heat, stirring constantly, until the sauce thickens, about 5 minutes. Season with Old Bay, salt, and pepper. Taste and adjust — the Old Bay does a lot of work here, so be generous if you like a bolder seafood flavor.

Fold In the Seafood

Remove the skillet from the heat. Gently fold in the lump crabmeat, turning carefully to keep the pieces intact — broken crab is still good but large lumps are better. Add the raw shrimp and fold again until evenly distributed.

Don’t pre-cook the shrimp. See the note in the opening.

Top and Bake

Pour the mixture into the prepared baking dish and spread into an even layer. Scatter the cheddar cheese over the top, then the breadcrumbs.

Bake at 375°F for 25 to 30 minutes until the top is golden brown and the casserole is visibly bubbling around the edges. The shrimp should be fully pink and opaque throughout — if any are still translucent in the center, give it another 5 minutes.

Garnish with chopped fresh parsley. Serve immediately.

Making It Ahead

The casserole can be assembled up to 24 hours in advance and refrigerated, covered, without the breadcrumb topping. Add the cheddar and breadcrumbs right before it goes in the oven. Add 5 to 10 minutes to the bake time if going from cold.

What to Serve Alongside

• Crusty bread for the sauce — there will be plenty
• Steamed white rice or wild rice underneath the casserole instead of alongside
• A simple green salad with lemon vinaigrette to cut through the richness
• Roasted asparagus or green beans

Variations

Swap cheddar for Gruyère for a nuttier, more sophisticated topping — particularly good if you’re serving this at a dinner party.

Add a dash of hot sauce or a pinch of cayenne to the cream sauce for background heat.

The sauce works with other seafood: scallops, lobster, or a mix of whatever’s fresh. Keep the total seafood weight at about 2 lbs for this size casserole.

Make This for Your Next Gathering

This is one of those casseroles that looks more involved than it is. The sauce comes together in about 10 minutes on the stove, the seafood goes in raw, and the oven does the rest. You can assemble it the night before and bake it fresh, which makes it legitimately practical for company.

Tell me in the comments which seafood combination you used and whether you went with panko or regular breadcrumbs. Rate the recipe, save it on Pinterest, and subscribe for more.

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