One of my favorite seafood dishes is my Baked Seafood Casserole. Loaded with fresh flounder, shrimp, sea scallops, and crab meat, every bite is full of flavor and seafood!

My easy seafood casserole recipe is perfect for your next dinner party, date night or just to make family dinner and extra special event.
Perfect for seafood lovers this easy seafood casserole will soon become one of your favorite recipes! Easy to make and so very delicious, it’s a winning combination.
Ingredients to make Baked Seafood Casserole
Let’s start by gathering the ingredients we need to make Baked Seafood Casserole. In Chef Speak this is called the “Mise en Place” which translates to “Everything in its Place”.
Not only does setting your ingredients up ahead of time speed up the cooking process, it also helps ensure you have everything you need to make the dish.
I used flounder, sea scallops, shrimp and lump crabmeat but feel free to use your favorite fish and seafood you have on hand to make this delicious casserole.
This sauce is made up of chicken broth, heavy cream, dijon mustard, black pepper, granulated onion, and granulated garlic. Feel free to add your own touch with Worcestshire sauce, lemon juice, parmesan cheese (or other cheese), and even a little sour cream. Just remember it’s all about the fresh seafood, don’t overpower it with the sauce.
What is a beurre- manie?
A beurre manie is pieces of butter rolled and pressed into flour so the flour adheres to the butter. This acts as a thickening agent. It’s used many times for thickening sauces at the end of the cooking process. You need enough flour to be able to coat the butter. The flour can be saved for another recipe.
How to make Seafood Casserole?
- Add two tablespoons of butter to a large skillet over medium-high heat. Melt the butter, then add the shrimp and scallops to the hot pan. ( you can substitute olive oil for the butter for sauteing the seafood)
- Saute the shrimp and scallops for about a minute, just long enough to sear the outside of the seafood.
- Add a splash of white wine to deglaze the pan, then add the heavy cream, chicken broth, dijon mustard, and seasonings to the pan.
- Saute the mixture for one minute, then remove the shrimp and scallops from the pan. Set aside until needed.
- Add two tablespoons of butter dredged in flour (beurre manie) to the seafood sauce. This will thicken the sauce. Let it simmer over low heat to thicken.
- Remove the pan from the heat and add the scallops, shrimp, and crab meat to the sauce. Mix until seafood is coated and set aside until needed.
- Place the flounder fillets in the bottom of a casserole dish. Add a little water (1-2 tablespoons) to the dish and sprinkle with old bay seasoning.
- Bake the flounder for 10 minutes at 350° F. Drain the water off the flounder.
- Add the seafood mixture to the casserole dish. Sprinkle with old bay seasoning.
- Bake for 25 minutes at 350° F until golden brown.
*Feel free to sprinkle bread crumbs on the top of the seafood casserole if you’d like to add a little crunch to the topping.
I always add a sprinkle of chopped Italian parsley to the food I serve, just for a little pop of color. The appearance of a dish is almost as important as the taste. First impressions can make or break a dish.
I have no doubt this will become a family favorite and you’ll be sharing my seafood casserole recipe with friends and family.
Recipe FAQ’s
I like mild fish, such as flounder for the bottom layer of the seafood casserole. Tilapia, turbot, sole, cod or halibut are also good choices.
I love serving this dish with rice, buttered noodles, or garlic mashed potatoes. Add a green vegetable or a salad and you got a feast!
I like lump crabmeat, but claw, Dungeness, king crab, or snow crab meat would also work well.
Raymond Benash
A great mother recipe, thanks. I did some mods on the fish contents based on what I had on hand, easy to adjust as I had no scallop but plenty of everything else.
The sauce base worked very well. I might add more than 2TB of the Beurre manié, just to thicken things up a bit more. I did have lobster roe butter in the freezer that made things a little more special.
I save all the liquid from prepping the cod, added some lobster jux I had in the freezer then topped off with the chicken stock to volume recommended.
Topped with a little cracker crumb, add a tad more Old Bay.
Nice one – will be keeping this as a base recipe for sure.
Connie
Can I double this recipe?
Chef Dennis Littley
Absolutley.
Michael
I am cooking it a little longer. Mine is definitely soupy. Maybe I did not thicken the sauce enough.
Chef Dennis Littley
That is a good possibility.
Dianna
I’m curious…why would you use chicken stock in this recipe rather shrimp, lobster, or seafood stock?
Chef Dennis Littley
seafood stocks have a soft flavor and affect the palate differently, which is why I generally use chicken stock. It basically is adding a flavor punch with a more pleasing flavor profile. You don’t use enough to make it taste like chicken. If do use lobster and shrimp bases for specific sauces, but sometimes use a little chicken base for the boost.
Cindy Alarcon
I love all the ingredients in this recipe and can’t wait to try it. However, the sodium is high. Not sure which ingredient is the culprit. What do you suggest I substitute to bring down the sodium?
Chef Dennis Littley
The scallops and crabmeat are the culprits. Both are naturally high in sodium. The other contributor is the chicken broth. You can use a low sodium chicken broth but other than cutting back on the amount of scallops and crabmeat there isn’t a lot else you can do to reduce the sodium.
Jeff
Wife & I made this recipe from Chef Dennis tonight. Awesome! We live in FL and are big seafood fans. My wife is from Maine and loves the way they cook seafood. This was delicious, definitely a keeper.
Denise Logsdon
Thanks for your reply. Ok to make the day before ? Use 2 casserole dishes – what size? Planning to make 6 servings
Denise Logsdon
Thinking about making this for company this weekend. Is it soupy? Wondering about crushing up a few ritz crackers to absorb some of the liquid?
Chef Dennis Littley
it shouldn’t be soupy, I don’t think I would add crackers but its entirely up to you.
Daniel
Sorry, but I don’t understand
6) Add 2 Tbs butter dredged in flour. How much flour?
9) Add a little water to the dish. How much is a “little”?
Thanks
Chef Dennis Littley
You need enough flour to roll the butter in, 1/4 cup. as for the water try 1 tablespoon
Leon
After reading directions, I want to make sure, if adding the shrimp and scallops back in for final 25 minutes, does that cause over cooking? Definitely want to try this recipe.
Chelsea
Does it matter if I use cooked or uncooked crab meat? Can I use canned also? Thanks!
Chef Dennis Littley
I have never worked with raw crab meat, so I can’t advise on that. If you’re talking about pasteurized crab meat, that is fine. If you’re talking about canned crab meat like canned tuna, yes, you can use it, but I don’t think that would be a good choice.
Roger L Pyle
I want to make this next weekend but the one instruction I don’t understand is “Add two tablespoons of butter dredged in flour (beurre manie) to the seafood sauce.” How does one dredge butter in flour? Can you just add flour as needed to get the thickening you desire? Would cornstarch work as well? This seems to be a critical step and I don’t want to get it wrong. Thanks!
Chef Dennis Littley
take the butter pieces and push them into the flour so the pieces are well coated. Do not add flour directly and corn starch is not a good alternative.
Debbie
Made this for our Christmas gathering. Everyone loved it. My son said he didn’t know what it was called, but it needs to be our tradition! Took a minute to get the thickening right, but it finally worked! ❤️
Jennifer Jordan
Love this. Made it 3x’s in 2 months. After the first time, I did learn to tweek and do better the next time. Getting that sauce to get thick was tricky for me, but I got it. Thanks for the recipe Chef Dennis.