Seafood Lasagna with Shrimp and Crab (Creamy White Sauce)

Published: November 1, 2026

It’s the last night of October as I write this, the kind of cold, dark evening when a casserole in the oven feels like the right answer to everything. This seafood lasagna with shrimp and crab is what I make when I want that cozy baked-pasta feeling but dinner still needs to feel a little special, the pan I pull out for company or a quiet holiday-weekend meal.

I’ll be honest: most versions of this dish let the seafood down. Shrimp that went in fully cooked comes out like pencil erasers, and crab bakes into stringy sadness. This one fixes both problems, and the fix takes about ninety seconds of extra work.

What goes into seafood lasagna with shrimp and crab

The shopping list is shorter than it looks. Here’s what matters at the store:

Shrimp. One pound of large shrimp (the 31/40 count bag), peeled and deveined. I cut each one into two or three pieces so every forkful gets shrimp instead of one giant piece per layer.
Crab. A pound of lump crab meat. The refrigerated pasteurized tubs near the seafood counter are fine; you don’t need fresh-picked. Pick through it for shell bits either way.
Noodles. Twelve regular lasagna noodles, boiled two minutes shy of the box time. Oven-ready noodles work with extra milk in the sauce, which I’ve noted in the recipe card.

Cheeses. Whole-milk ricotta (skim gets grainy when baked), low-moisture mozzarella so the top browns instead of weeping, and Parmesan you grate yourself.
The flavor base. Butter, a shallot, garlic, flour, milk, cream, lemon zest, nutmeg and Old Bay. The Old Bay does quiet work here; don’t skip it.

On the shallot: it melts into the sauce in a way a chopped onion never quite does, sweeter and softer. A small yellow onion is a fine stand-in, just mince it smaller than you think you need to.

A good seafood lasagna with shrimp and crab is really three simple parts: sauce, cheese filling, seafood. Get each one mostly right and the oven handles the rest.

Raw shrimp, lump crab meat, lasagna noodles and white sauce ingredients arranged on a marble counter

The white sauce should be looser than you think

Melt the butter, soften the shallot, let the garlic smell like garlic for about thirty seconds, then whisk in the flour and give it a minute to lose its raw edge. The milk goes in warm, a splash at a time at first, whisking between additions so the roux relaxes instead of clumping.

You’re looking for a sauce that coats the back of a spoon but still pours easily, thinner than gravy. It will look too loose. It isn’t. The noodles drink sauce for the entire 45-minute bake, and a sauce that starts thick comes out of the oven as paste.

This is the same reason I keep the ricotta loose and lemony in my One Pot Lemon Ricotta Pasta: pasta keeps absorbing liquid long after you think it’s done.

Off the heat, stir in the nutmeg, Old Bay, lemon zest, salt, pepper and Parmesan. Taste it. The sauce should be slightly saltier than feels right, because a pound of unseasoned seafood is about to dilute it.

Creamy white sauce being whisked in a stainless saucepan on the stove

Where most seafood lasagna goes wrong

Here’s the part that matters: the seafood should not be fully cooked when it goes into the pan. Shrimp needs only about five minutes of heat total, and it’s getting forty-five inside the lasagna. I sear my pieces for 60 to 90 seconds in hot oil, just until the edges blush pink, then pull them off the heat. Adding them completely raw works too. Either way, they finish in the oven and stay tender.

Lump crab is already cooked when you buy it, so it needs zero heat of its own. Folding it gently into the ricotta insulates it from direct oven heat and keeps the lumps intact instead of shredded to threads.

Every complaint I’ve ever heard about seafood lasagna with shrimp and crab comes back to this section. If you want a number: fish and shellfish are done at 145°F, per the safe minimum internal temperature chart. Inside a bubbling lasagna they get there fast, which is exactly the argument against pre-cooking.

Shrimp pieces searing in a hot skillet, just starting to turn pink at the edges

Layering seafood lasagna with shrimp and crab

Order matters more than neatness. Start with a cup of sauce on the bottom of a greased 9×13 pan so the first noodles have something to sit in and nothing sticks. Then the pattern goes: noodles, a third of the crab-ricotta mixture dotted over them, a third of the shrimp scattered on, a sprinkle of mozzarella, more sauce.

Repeat that twice more, then finish with the last noodles, every drop of remaining sauce, and the rest of the mozzarella plus a final shower of Parmesan. The top noodles must be fully covered in sauce or the edges bake into crisp, uncuttable shards.

Don’t stress about spreading the ricotta layer perfectly even. It settles in the oven, and a slightly lumpy seafood lasagna with shrimp and crab slices into better-looking layers than a strained, over-smoothed one. Dollop and move on.

A baking dish being layered with noodles, crab-ricotta filling and shrimp pieces

Baking, resting, and the hard part

Cover the pan with foil (spray the underside first so the cheese doesn’t glue itself to it) and bake at 375°F for 25 minutes. Pull the foil and go another 15 to 20, until the edges are actively bubbling and the top has golden patches.

Then walk away for 15 to 20 minutes. I know. But a seafood lasagna with shrimp and crab that gets cut straight from the oven slumps into a cheesy puddle. Give it the rest and it cuts into tall, distinct layers that actually look like the pictures.

You’ll know it’s ready when a knife slides through the center noodles with no resistance and the sauce at the edges looks thick and glossy, not watery. The whole kitchen will smell like butter, garlic and the sea in the best way.

A cut square of seafood lasagna with shrimp and crab on a spatula showing creamy layers

A few swaps that work (and one that doesn’t)

The nice thing about seafood lasagna with shrimp and crab is how forgiving it is once you respect the one real rule: nothing goes in fully cooked.

Bay scallops or chopped sea scallops slide right in alongside the shrimp with no changes. A handful of chopped cooked lobster turns this into a very good special-occasion pan. A layer of well-drained spinach between the ricotta and shrimp is nice if you want something green inside.

Cottage cheese can stand in for ricotta if you blend it smooth first. Jarred Alfredo can stand in for the white sauce in a real pinch; thin it with half a cup of milk and add the lemon zest and Old Bay yourself.

The swap I’d skip: red sauce. Tomato and lemon fight each other, and the acid flattens the sweetness of the crab. This dish wants to be white.

What to serve alongside

The pan is rich, so I keep everything around it green and sharp. A salad with a lemony vinaigrette, or a tray of my Roasted Zucchini, does the job without competing. Crusty bread is allowed but not required; there’s plenty going on already.

If this puts you in a seafood mood, my Sheet Pan Orange Ginger Salmon with Broccoli is the weeknight version of this energy, and the Shrimp Tacos handle the faster, louder end of the spectrum. And on a night when you want that same creamy-garlicky sauce with beef instead, the Garlic Butter Steak Bites & Creamy Alfredo Tortellini scratches the itch.

Making it ahead and keeping leftovers

You can assemble the whole pan a day ahead, wrap it tight and refrigerate it. Bake it straight from the fridge, adding 10 to 15 minutes to the covered time. For longer storage, freeze this seafood lasagna with shrimp and crab unbaked for up to two months and thaw it overnight in the fridge before baking.

Leftover slices keep 3 to 4 days in a covered container, which lines up with the USDA’s cold food storage guidance for cooked seafood. Reheat covered at 325°F, or microwave a slice with a splash of milk over the top so the sauce loosens back up instead of tightening into a brick.

It’s a fair amount of pan for a Tuesday, and that’s kind of the point. One afternoon of layering and there’s a seafood lasagna with shrimp and crab that makes the whole house smell like you tried much harder than you did.