In a skillet over medium heat, melt 2 tablespoons of butter and sauté 3 minced garlic cloves until fragrant, about 1 minute. Add 1 cup of lobster meat and 1 cup of crab meat, cooking gently for 3–4 minutes until heated through. Remove from heat and let your seafood mixture cool slightly.

In a large mixing bowl, combine the cooled seafood mixture with 8 ounces of cream cheese and 1 cup of shredded mozzarella. Season with salt and pepper to taste, mixing everything thoroughly until well-blended. Set this creamy filling aside.

Bring a large pot of salted water to a boil and cook 12 jumbo pasta shells until al dente, according to the package instructions, about 10–12 minutes. Once cooked, drain and rinse the shells under cold water to stop the cooking process. Set them aside to cool completely.

In the same skillet used for the seafood, melt 2 tablespoons of butter over medium heat. Whisk in 2 tablespoons of flour and cook for 1–2 minutes to form a roux. Gradually add 1 cup of heavy cream, whisking until smooth and thickened, about 3–4 minutes. Stir in ½ cup of grated Parmesan cheese until melted and set aside.

Preheat your oven to 375°F (190°C). Pour a thin layer of cheese sauce into a 9x13 inch baking dish, just enough to cover the bottom. Using a spoon, fill each cooled pasta shell with the creamy seafood filling and arrange them in the baking dish. Pour the remaining cheese sauce evenly over the stuffed shells.

Cover the baking dish with aluminum foil and bake for 20 minutes. After 20 minutes, remove the foil and bake for another 10 minutes, or until the cheese is bubbly and golden on top.

Once baked, let the creamy seafood stuffed shells cool for about 5 minutes before serving. Garnish with freshly chopped parsley if desired.