Quick Recipe Version (TL;DR)
Quick Ingredients
- 12 oz (340 g) penne or medium pasta shells
- 1 lb (454 g) large shrimp, peeled and deveined
- 1 lb (454 g) sea scallops, side muscle removed
- 2 tbsp olive oil, divided
- 4 tbsp (56 g) unsalted butter
- 4 cloves garlic, minced
- 2 tbsp all-purpose flour
- 2 cups (480 ml) whole milk
- 1 1/2 cups (360 ml) heavy cream
- 1 1/2 cups (150 g) finely grated Parmesan cheese
- 1 tsp kosher salt, plus more for pasta water
- 1/2 tsp freshly ground black pepper
- 1/4 tsp ground nutmeg (optional)
- 2 tbsp fresh lemon juice
- 1/4 cup chopped fresh parsley, plus more to serve
- 2 cups (200 g) shredded low-moisture mozzarella
Do This
- 1. Heat oven to 400°F (205°C). Grease a 9×13-inch baking dish.
- 2. Boil pasta in well-salted water until 2 minutes shy of al dente; drain.
- 3. Quickly sear shrimp and scallops in olive oil just until barely cooked; transfer to a plate.
- 4. Make Alfredo sauce: butter + garlic, whisk in flour, then whisk in milk and cream; simmer until thick.
- 5. Off heat, stir in Parmesan, salt, pepper, (nutmeg), lemon, and parsley.
- 6. Toss pasta with sauce and seafood, spread into dish, top with mozzarella.
- 7. Bake 15–18 minutes until bubbly; broil 1–2 minutes to brown. Rest 10 minutes and scoop to serve.
Why You’ll Love This Recipe
- Creamy, crowd-friendly comfort food: rich Parmesan Alfredo meets a bubbly, golden baked top.
- Seafood stays tender: a quick sear plus a short bake prevents rubbery shrimp and scallops.
- Make-ahead flexible: assemble earlier, bake when you’re ready.
- Easy to serve: scoops beautifully for potlucks, holidays, and family-style dinners.
Grocery List
- Seafood: 1 lb large shrimp (peeled/deveined), 1 lb sea scallops
- Produce: garlic, lemon, fresh parsley
- Dairy: unsalted butter, whole milk, heavy cream, Parmesan cheese, shredded mozzarella
- Pantry: penne or medium shells, olive oil, all-purpose flour, kosher salt, black pepper, ground nutmeg (optional)
Full Ingredients
Pasta
- 12 oz (340 g) penne or medium pasta shells
- Salt for pasta water (use 1 1/2 tbsp kosher salt for 4 quarts/3.8 L water)
Seafood
- 1 lb (454 g) large shrimp, peeled and deveined (tails off)
- 1 lb (454 g) sea scallops, side muscle removed
- 1 tbsp olive oil (for shrimp)
- 1 tbsp olive oil (for scallops)
- 1/2 tsp kosher salt (to season seafood)
- 1/4 tsp freshly ground black pepper (to season seafood)
Parmesan Cream Sauce (Alfredo-Style)
- 4 tbsp (56 g) unsalted butter
- 4 cloves garlic, minced (about 1 1/2 tbsp)
- 2 tbsp all-purpose flour
- 2 cups (480 ml) whole milk
- 1 1/2 cups (360 ml) heavy cream
- 1 1/2 cups (150 g) finely grated Parmesan cheese (plus more for serving, optional)
- 1/2 tsp kosher salt (plus more to taste)
- 1/4 tsp freshly ground black pepper (plus more to taste)
- 1/4 tsp ground nutmeg (optional, but great with cream sauce)
- 2 tbsp fresh lemon juice
- 1/4 cup chopped fresh parsley
For Baking
- 2 cups (200 g) shredded low-moisture mozzarella
- Butter or nonstick spray for the baking dish
Step-by-Step Instructions
Step 1: Preheat the oven and prep the baking dish
Arrange a rack in the upper-middle of the oven and preheat to 400°F (205°C). Grease a 9×13-inch baking dish with butter or nonstick spray.
Set out the mozzarella and Parmesan so they’re ready when the sauce is hot (this helps them melt smoothly).
Step 2: Boil the pasta just shy of al dente
Bring a large pot of water to a boil. Add 1 1/2 tbsp kosher salt (for about 4 quarts/3.8 L water). Cook 12 oz pasta until 2 minutes shy of the package’s al dente time.
Drain well. Do not rinse. (The starch on the pasta helps the sauce cling.)
Step 3: Quickly sear the shrimp
While the pasta cooks (or right after), pat the shrimp dry with paper towels. Season with a pinch of the 1/2 tsp salt and 1/4 tsp pepper.
Heat 1 tbsp olive oil in a large skillet over medium-high heat. Add shrimp in a single layer and cook for 60–90 seconds per side, just until pink and barely cooked through.
Transfer shrimp to a plate.
Step 4: Sear the scallops for flavor (without overcooking)
Pat scallops very dry (this is key for browning). Season with the remaining pinch of salt and pepper.
Wipe out the skillet if there are browned bits that look too dark, then heat 1 tbsp olive oil over high heat until shimmering. Add scallops in a single layer, leaving space between them.
Sear for 60–90 seconds without moving, until a golden crust forms. Flip and cook 30–60 seconds more. They should still be slightly translucent in the center; they’ll finish in the oven. Transfer to the plate with the shrimp.
Step 5: Make the Parmesan cream sauce
Reduce heat to medium. Add 4 tbsp butter to the skillet. When melted, add minced garlic and cook for 30 seconds, just until fragrant.
Whisk in 2 tbsp flour and cook for 60 seconds, whisking constantly (this removes the raw flour taste).
Slowly whisk in 2 cups milk, then whisk in 1 1/2 cups heavy cream. Bring to a gentle simmer, whisking frequently, and cook for 3–5 minutes until the sauce thickens enough to coat the back of a spoon.
Turn heat to low. Add Parmesan a handful at a time, whisking until smooth. Stir in 1/2 tsp kosher salt, 1/4 tsp pepper, and nutmeg (if using). Off heat, stir in 2 tbsp lemon juice and 1/4 cup parsley. Taste and adjust salt/pepper if needed.
Step 6: Combine pasta, sauce, and seafood
Add the drained pasta to the sauce and toss until evenly coated. Gently fold in the shrimp and scallops (and any juices on the plate) so the seafood stays intact.
Spoon the mixture into the prepared baking dish and spread into an even layer.
Step 7: Top with mozzarella and bake until bubbly and browned
Sprinkle 2 cups shredded mozzarella evenly over the top.
Bake at 400°F (205°C) for 15–18 minutes, until the edges are bubbling. For a deeper golden top, broil on high for 1–2 minutes, watching closely so it doesn’t burn.
Let the bake rest for 10 minutes before serving. This helps it set up for neat, crowd-friendly scoops. Finish with a little extra parsley (and Parmesan, if you like).
Pro Tips
- Don’t overcook the seafood up front: sear quickly and leave it slightly underdone; the oven will finish it gently.
- Dry scallops = better browning: pat them very dry and don’t move them while searing.
- Grate your own Parmesan: finely grated Parmesan melts smoother than pre-shredded and gives a silkier sauce.
- Stop the pasta early: undercooking by 2 minutes keeps it from turning soft in the bake.
- Keep the sauce loose: it will thicken as it bakes and again as it rests.
Variations
- Add vegetables: stir in 2 cups baby spinach (wilt it into the sauce) or 1 cup thawed frozen peas before baking.
- Swap the seafood: use 1 lb shrimp + 1 lb lump crab (fold crab in off heat), or replace scallops with chopped lobster meat.
- Add a crunchy topping: mix 3/4 cup panko with 2 tbsp melted butter and 2 tbsp Parmesan; sprinkle over the mozzarella before baking.
Storage & Make-Ahead
Refrigerate: Cool completely, then cover and refrigerate for up to 3 days.
Reheat: For best texture, reheat covered in a 350°F (175°C) oven for 20–25 minutes until hot in the center. Uncover for the last 5 minutes to re-crisp the top. Individual portions can be microwaved, but seafood can overcook; use 50% power in short bursts.
Make-ahead (best method): Assemble the casserole up to the point of baking, cover tightly, and refrigerate up to 24 hours. Bake at 400°F (205°C) for 20–25 minutes (it takes longer from cold), then broil 1–2 minutes if desired.
Freezing note: Cream sauces can separate after freezing and thawing. If you must freeze, freeze tightly wrapped for up to 1 month and reheat gently, adding a splash of milk or cream if the sauce looks broken.
Nutrition (per serving)
Approximate, based on 10 servings: 560 calories, 33 g protein, 46 g carbohydrates, 28 g fat, 14 g saturated fat, 210 mg cholesterol, 820 mg sodium, 2 g fiber, 6 g sugar.
