1. Cook the pasta and broccoli: Bring a large pot of water to a boil and add a generous pinch of salt (skip the salt if using jarred alfredo sauce). Cook the pasta according to package instructions. Add the broccoli to the boiling water during the last 2 minutes of cooking, just until crisp tender. Drain the pasta and broccoli together and set aside. While pasta cooks, move on to Steps 2 and 3.
2. Preheat the oven: Preheat your oven to 375°F (190°C). Lightly grease a 9×9-inch baking dish.
3. Prepare the Alfredo Sauce: (skip this step if using a jar from the store) In a medium saucepan over medium heat, melt the butter until it begins to bubble gently. Using a whisk, stir in the flour and whisk for about 1 minute. Whisk in the chicken broth and the milk until smooth. Bring to a low simmer and cook for 1-2 minutes, until slightly thickened, whisking continually. Remove from the heat. Whisk in the grated Parmesan, salt, and pepper until well combined.
4. Combine: In the pot you cooked the pasta in, combine the cooked pasta and broccoli, rotisserie chicken, Alfredo Sauce, garlic powder, Italian seasoning, and 1/2 cup shredded mozzarella (reserve the rest). Gently stir until evenly combined.
5. Assemble the casserole: Pour the mixture into the prepared 9×9-inch pan. Sprinkle 1/4 cup Parmesan cheese and the remaining 1/2 cup mozzarella cheese evenly over the top.
6. Bake: Bake on the middle rack for 20-25 minutes, or until the cheese is melted and bubbly. Optional: Turn on the broiler for 1 to 2 minutes, just until it starts to get a little golden on top (watch closely!). Top with fresh chopped parsley, if desired. Serve warm.

Freezer Meal Instructions:

To Freeze: Assemble the casserole (through Step 5), but do not bake. Cover tightly with several layers of plastic wrap and/or foil, label, and freeze.

To Prepare: Thaw about 24 hours in the refrigerator. Bake according to directions in Step 6.