Preheat oven to 375°F and spray a 9x13-inch baking dish with cooking spray.
Add the uncooked pasta, raw shrimp, heavy cream, chicken broth, cream cheese cubes, 1 cup of mozzarella, Parmesan cheese, garlic, Italian seasoning, red pepper flakes, salt, and pepper to the baking dish.
Stir everything together until well combined, making sure the pasta is submerged in the liquid.
Cover tightly with aluminum foil and bake for 30 minutes.
Remove the foil, stir the casserole gently, then sprinkle the remaining 1 cup of mozzarella cheese on top.
Return to the oven uncovered and bake for an additional 5-10 minutes, until the cheese is melted and bubbly.
Garnish with fresh parsley and let rest for 5 minutes before serving.