Preheat your oven to 375°F (190°C) and grease a baking dish.

Cook the large pasta shells according to package instructions until they’re al dente; drain carefully.

Combine softened cream cheese, shrimp, crab meat, minced garlic, chives, and half of the Parmesan cheese in a mixing bowl. Mix until well incorporated.

Stuff each shell generously with the seafood mixture and place them seam-side up in the prepared baking dish.

Simmer heavy cream and lemon juice in a saucepan over medium heat until slightly thickened.

Pour the creamy sauce over the stuffed shells and sprinkle with the remaining Parmesan cheese. Cover with foil and bake for about 25 minutes, then remove the foil and bake for an additional 10 minutes until golden brown.