1. Preheat the oven to 375°F and lightly grease a 9×13-inch baking dish.

2. Bring a large pot of salted water to a boil and cook the pasta shells until just al dente, then drain and set aside.

3. Pat the shrimp dry and season them with salt, black pepper, and red pepper flakes.

4. Heat the olive oil and 1 tablespoon of butter in a large skillet over medium-high heat, then cook the shrimp for about 1 minute per side until just turning pink. Remove the shrimp and set aside.

5. In the same skillet, melt the remaining butter and cook the shallot until softened.

6. Add the garlic and stir for about 30 seconds until fragrant.

7. Pour in the chicken broth, lemon juice, and lemon zest, scraping up any flavorful bits from the pan.

8. Stir in the heavy cream and Italian seasoning, then simmer for 2 to 3 minutes.

9. Add the Parmesan cheese and stir until the sauce is smooth and slightly thickened.

10. Add the cooked pasta to the skillet and toss until coated in the sauce.

11. Fold in the shrimp and 1 tablespoon of chopped parsley.

12. Transfer the mixture to the prepared baking dish and top with the mozzarella cheese.

13. Bake for 15 to 20 minutes until hot and bubbly.

14. Broil for 1 to 2 minutes if needed for a more golden top.

15. Sprinkle with the remaining parsley and serve warm.