Step 1: Prepare the Tortellini
Bring a large pot of salted water to a boil. Add the cheese tortellini and cook according to the package instructions (usually 3-5 minutes). Drain and set aside. Be careful not to overcook—the tortellini will continue cooking in the oven.

Step 2: Season and Cook the Shrimp
While the tortellini is cooking, season the shrimp with olive oil, garlic powder, onion powder, salt, and pepper. In a large skillet over medium heat, cook the shrimp for 2–3 minutes on each side or until pink and opaque. Remove from heat and set aside.

Step 3: Make the Alfredo Sauce
In the same skillet, melt the butter over medium heat. Add the minced garlic and cook for about 1 minute until fragrant. Whisk in the flour and cook for 1 more minute to make a roux. Slowly pour in the heavy cream and milk, whisking constantly to prevent lumps.

Step 4: Add Cheese and Seasoning
Reduce heat to low. Stir in Parmesan cheese and 1 cup of mozzarella until melted and smooth. Add Italian seasoning, crushed red pepper flakes (if using), and adjust salt and pepper to taste. Let simmer for 2-3 minutes until thickened.

Step 5: Assemble and Bake the Casserole
Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish. Combine the cooked tortellini and shrimp in a large mixing bowl. Pour in the Alfredo sauce and gently stir to coat everything evenly. Transfer the mixture to the prepared casserole dish. Top with the remaining mozzarella cheese. Bake uncovered for 20–25 minutes, or until bubbly and golden brown on top. Garnish with chopped parsley before serving.