Begin by bringing a large pot of salted water to a rolling boil. Cook the large pasta shells al dente according to the package instructions (9-11 minutes). Drain, rinse under cold water, and set aside.

In a spacious mixing bowl, combine seafood, softened cream cheese, grated cheese, minced garlic, and seasonings. Fold until well combined.

In a medium saucepan, melt butter over medium heat. Stir in flour to create a roux, and gradually whisk in milk until thickened (5-7 minutes). Season with salt and pepper.

Stuff each cooled pasta shell with the seafood filling and place them seam-side up in a greased baking dish.

Preheat your oven to 180°C (350°F). Spread a layer of sauce across the bottom of the baking dish, arrange stuffed shells, then pour remaining sauce over them. Sprinkle extra grated cheese.

Cover with foil and bake for 25-30 minutes until bubbling. Remove foil and bake for another 10 minutes until golden.