In a large skillet, melt 2 tablespoons of butter over medium heat. Add minced garlic and sauté until fragrant, about 1 minute.

Fold in the lobster and crab, cooking for an additional 2–3 minutes until heated through. Transfer the mixture to a bowl and set aside to cool slightly while preparing the filling.

In a mixing bowl, blend the cooked seafood mixture with 8 ounces of cream cheese and 1 cup of shredded mozzarella until smooth and well combined.

Bring a large pot of salted water to a boil and cook 12–15 jumbo pasta shells according to package instructions until al dente. Drain gently and rinse under cold water to stop cooking.

Return the skillet to medium heat and melt 4 tablespoons of butter. Whisk in ¼ cup of flour until smooth and cook for about 1 minute. Gradually pour in 1½ cups of heavy cream and ½ cup of grated Parmesan cheese, whisking constantly.

Preheat your oven to 375°F (190°C). Spread a thin layer of the creamy sauce onto the bottom of a baking dish. Stuff each cooled jumbo shell with the seafood filling and place them evenly in the dish.

Pour the remaining creamy sauce over the top, ensuring that each shell is generously coated. Cover the dish with aluminum foil and bake for 20 minutes.

Remove the foil and bake for an additional 10 minutes until the sauce is bubbly and golden.

Allow the dish to cool for about 5 minutes. Garnish with fresh herbs if desired, and serve.