Creamy Seafood Gratin with Scallops Shrimp

Creamy Seafood Gratin with Scallops Shrimp tastes rich, buttery, and slightly briny, with a golden cheesy crust that crackles when your spoon breaks through. It works perfectly for date night, holidays, or a cozy weeknight treat, and you can get it on the table in about 45–55 minutes. I first made a version of this when I lived in a tiny apartment with a toaster oven and still felt like I ran a fancy bistro out of my kitchen.

Why Make This Creamy Seafood Gratin with Scallops Shrimp at Home

You control everything at home, from how many scallops you pile in to how bubbly and browned you want the top. Restaurant seafood gratin often costs a lot and skimps on the good stuff, while your baking dish can overflow with shrimp and scallops for a fraction of the price.

You also skip mystery thickeners and heavy salt. You can use real cream, real butter, and seafood you trust, and adjust the seasoning exactly how you like it.

“This Creamy Seafood Gratin with Scallops Shrimp tastes like a fancy coastal restaurant special, only cozier and loaded with way more seafood.”

Ingredients You Need

Seafood

• Large sea scallops
  • Pat them very dry so they brown instead of steaming.
  • If they seem very wet, line a plate with paper towels and chill them uncovered for 20–30 minutes.
• Large raw shrimp, peeled and deveined
  • Use 16/20 or 21/25 size for a meaty bite.
  • Frozen shrimp work great; thaw them overnight in the fridge or under cold running water, then dry well.

Vegetables and aromatics

• Yellow onion, finely diced
• Leek, white and light green parts only, thinly sliced (optional but adds sweetness)
• Celery, finely diced
• Garlic cloves, minced
• Fresh parsley, chopped
• Fresh chives or green onions, sliced, for garnish

You can swap leek with extra onion if you do not have it. I like to keep a bag of frozen mirepoix in the freezer and use that as a shortcut when I feel tired.

Fats and dairy

• Unsalted butter
• Olive oil or neutral oil
• Heavy cream
• Whole milk or half and half
• Grated Gruyère cheese
• Grated Parmesan cheese

Gruyère melts silky and nutty, which suits seafood beautifully. If you cannot find it, use Swiss cheese or a mix of mozzarella and a bit of Parmesan.

Flavor boosters

• Dry mustard powder
• Smoked paprika or sweet paprika
• Lemon zest and lemon juice
• Dijon mustard
• Old Bay seasoning or a similar seafood seasoning blend
• Kosher salt
• Freshly ground black pepper
• Pinch of cayenne or red pepper flakes (optional, for a gentle kick)

Old Bay already contains salt, so taste as you go and adjust. If you do not keep Old Bay, use a mix of paprika, celery salt, a little garlic powder, and black pepper.

Thickener

• All purpose flour

You can use a gluten free all purpose blend that says it works as a 1:1 swap. Avoid almond or coconut flour here because they change the texture and flavor too much.

Breadcrumb topping

• Panko breadcrumbs
• Extra grated Parmesan
• Melted butter
• Pinch of salt and pepper
• Extra lemon zest (optional, but I love it)

Panko gives a lighter, crunchier crust than regular breadcrumbs. If you only have regular crumbs, use a little less so the topping does not feel heavy.

Equipment

• Large skillet or sauté pan
• Medium saucepan
• Mixing bowls
• Whisk
• 2 to 2.5 quart baking dish or individual gratin dishes / ramekins
• Cutting board and sharp knife
• Microplane or fine grater for lemon zest and Parmesan

Tips & Mistakes

• Pat scallops and shrimp very dry so they sear and caramelize instead of steaming and turning rubbery.
• Use medium heat for browning seafood and aromatics; high heat can scorch the fond and turn garlic bitter.
• Salt in layers and taste often so the gratin sauce stays balanced and not overly salty from cheese and seasoning blends.
• Warm milk and cream slightly before adding to the roux so the sauce thickens smoothly without lumps.
• Whisk constantly while you add liquid to the roux so the sauce stays silky and does not clump.
• Do not overcook the seafood on the stove; just kiss it with heat since it finishes in the oven.
• Spread seafood in a single layer in the baking dish so it cooks evenly and the sauce bubbles around it.
• Use shallow dishes if possible so the topping browns nicely and the center heats through quickly.
• Do not drown the topping in butter; coat the crumbs lightly so they crisp instead of turning greasy.
• Let the gratin rest 5–10 minutes after baking so the sauce thickens slightly and does not run all over the plate.

How to Make Creamy Seafood Gratin with Scallops Shrimp

Step 1: Sauté veggies and aromatics

Heat oil in a large skillet over medium heat. Add diced onion, leek, and celery, then cook until soft and lightly golden, about 7–8 minutes. Stir in garlic and cook 1–2 minutes, until you smell that sweet garlicky aroma. Season with a pinch of salt, pepper, and a little Old Bay, then transfer the mixture to a bowl.

Step 2: Sear the scallops and shrimp

Pat scallops and shrimp very dry with paper towels and season them with salt, pepper, and a little Old Bay. Add a small knob of butter to the same skillet over medium high heat. When the butter foams, add scallops in a single layer and sear 1–2 minutes per side until they develop a light golden crust, then move them to a plate. Sear shrimp in the same pan 1–2 minutes total, just until they turn pink at the edges, then add them to the plate with the scallops.

Step 3: Make the creamy gratin sauce

Lower the heat to medium and add butter to the skillet. When it melts, sprinkle in the flour and whisk constantly for 1–2 minutes until the mixture turns slightly golden and smells toasty. Slowly pour in warm milk and cream while you whisk, smoothing out any lumps as you go. Add Dijon, dry mustard, paprika, lemon zest, and a pinch of cayenne, then simmer 3–5 minutes until the sauce thickens to coat the back of a spoon.

Step 4: Add cheese and adjust seasoning

Turn the heat to low and stir in Gruyère and some Parmesan until they melt into the sauce. Taste and adjust with more salt, pepper, or Old Bay as needed, keeping in mind the topping adds more flavor. Stir in chopped parsley and a squeeze of lemon juice for brightness. The sauce should taste slightly salty and very flavorful since it coats all the seafood and vegetables.

Step 5: Assemble the gratin

Preheat your oven to 400°F. Spread the sautéed onion mixture in the bottom of your baking dish. Arrange scallops and shrimp evenly over the veggies, then pour the hot cheese sauce over the top, gently shaking the dish so the sauce settles around everything. You want the seafood mostly covered but not swimming in sauce.

Step 6: Mix the crunchy topping

In a small bowl, combine panko, Parmesan, a pinch of salt and pepper, and lemon zest if you use it. Drizzle in melted butter and toss with your fingers until the crumbs feel evenly coated and slightly clumpy. Sprinkle the breadcrumb mixture evenly over the gratin. Try to cover the surface without packing the crumbs down, so they crisp nicely.

Step 7: Bake until bubbly and golden

Place the baking dish on a sheet pan to catch any drips. Bake at 400°F for 15–20 minutes, until the top turns golden brown and the sauce bubbles around the edges. If the top browns too quickly, tent loosely with foil. Let the Creamy Seafood Gratin with Scallops Shrimp rest 5–10 minutes before serving so the sauce sets slightly.

Variations I’ve Tried

I often add a handful of frozen peas or blanched asparagus pieces to the baking dish for a built in veggie side. Sometimes I swap half the shrimp for chunks of firm white fish like cod or halibut, which soak up the sauce beautifully. If I feel extra indulgent, I tuck in a few pieces of lobster meat and cut back slightly on the shrimp.

You can go slightly lighter by using half and half instead of full heavy cream and adding a bit more stock or milk. I also like a garlicky herb version with fresh tarragon, dill, and extra lemon zest, which gives the gratin a brighter, almost springlike flavor. For spice lovers, a spoonful of harissa or a generous pinch of red pepper flakes in the sauce adds gentle heat that plays nicely with the cream.

How to Serve Creamy Seafood Gratin with Scallops Shrimp

Serve this Creamy Seafood Gratin with Scallops Shrimp with crusty bread or toasted baguette slices so you can scoop up every bit of sauce. A simple green salad with a tangy vinaigrette cuts through the richness and keeps the meal balanced. Steamed green beans, roasted broccoli, or sautéed spinach all pair nicely and soak up extra sauce. For a heartier plate, spoon the gratin over buttered rice, mashed potatoes, or a bed of plain pasta.

How to store

• Cool leftovers to room temperature, then cover tightly and store in the fridge for up to 2 days.
• For freezing, portion the gratin into small, freezer safe containers, press plastic wrap directly on the surface, then seal and freeze for up to 1 month.
• Reheat in a 325°F oven, covered, until hot in the center, then uncover for a few minutes to re crisp the topping.
• If you use a microwave, heat at 50 percent power in short bursts and stir gently so the sauce does not break and the seafood stays tender.

Creamy Seafood Gratin with Scallops and Shrimp

Creamy Seafood Gratin with Scallops and Shrimp is a rich, oven-baked seafood dish with a velvety cream sauce, tender shrimp, and scallops topped with a golden, cheesy crust.

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Prep Time 20 minutes mins

Cook Time 25 minutes mins

Total Time 45 minutes mins

Servings: 4

Course: Drinner

Cuisine: American

Ingredients

  

• 8 ounces sea scallops, patted dry
• 8 ounces medium shrimp, peeled and deveined
• 1 tablespoon olive oil
• 2 tablespoons unsalted butter
• 2 tablespoons all-purpose flour
• 1 1/4 cups whole milk
• 1/2 cup heavy cream
• 1/3 cup dry white wine
• 2 cloves garlic, minced
• 1/4 cup grated Parmesan cheese
• 1/2 cup shredded Gruyère or Swiss cheese
• 1/3 cup panko bread crumbs
• 2 tablespoons fresh parsley, chopped
• 1/4 teaspoon paprika
• 1/2 teaspoon kosher salt, plus more to taste
• 1/4 teaspoon freshly ground black pepper
• 1 tablespoon lemon juice
• 1 teaspoon lemon zest

Instructions

 

1. Preheat the oven to 400°F (200°C). Lightly butter a shallow baking dish or individual gratin dishes.
2. Pat the scallops and shrimp dry with paper towels. Season lightly with a pinch of salt and pepper.
3. Heat the olive oil in a skillet over medium-high heat. Add the scallops and shrimp and sear just until they start to turn opaque, 1–2 minutes per side. Transfer to a plate; they will finish cooking in the oven.
4. In the same skillet, reduce heat to medium and add the butter. Once melted, stir in the flour and cook, whisking constantly, for 1–2 minutes until lightly foamy but not browned.
5. Slowly whisk in the milk and heavy cream until smooth. Add the garlic, white wine (if using), salt, and pepper. Simmer, whisking, for 3–4 minutes until slightly thickened.
6. Remove the sauce from the heat and stir in the Parmesan cheese, lemon juice, and lemon zest. Taste and adjust seasoning with more salt and pepper if needed.
7. Arrange the seared scallops and shrimp in the prepared baking dish. Pour the creamy sauce evenly over the seafood.
8. In a small bowl, combine the Gruyère cheese, panko bread crumbs, parsley, and paprika. Sprinkle this mixture evenly over the top of the sauce.
9. Bake for 15–18 minutes, or until the top is golden brown and the sauce is bubbling around the edges.
10. Let the gratin rest for 5 minutes before serving to allow the sauce to set slightly. Serve hot with crusty bread or over rice or pasta.

Notes

Nutrition Information
Approximate per serving (4 servings): 520 calories; fat 33 g; saturated fat 17 g; carbohydrates 20 g; fiber 1 g; sugars 6 g; protein 34 g; sodium 780 mg. Values will vary based on specific ingredients, brands, and portion size.