In a large skillet, melt 2 tablespoons of butter and sauté 2 minced garlic cloves until fragrant, about 1 minute. Add fresh lobster and crab meat, cooking until heated through, about 3-4 minutes. Remove from heat and mix in 4 ounces of cream cheese and 1 cup of shredded mozzarella until smooth. Set aside.

In a large pot of boiling salted water, cook 12 jumbo pasta shells until al dente, about 9-11 minutes. Drain and rinse under cold water to stop cooking.

Using the same skillet, melt 2 tablespoons of butter, then whisk in 2 tablespoons of flour for 1 minute. Gradually whisk in 1 cup of heavy cream and bring to a simmer. Stir in ½ cup of grated Parmesan cheese until melted.

Preheat the oven to 375°F (190°C). Pour a thin layer of sauce into a 9x13-inch baking dish. Stuff each pasta shell with the seafood filling and place in the dish seam side up. Pour remaining sauce over shells.

Cover the dish with foil and bake for 20 minutes. Uncover and bake for an additional 10 minutes until bubbly.

Remove from oven, let cool for a few minutes, and serve warm, garnished with more Parmesan or fresh herbs.