Preheat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish.
In a saucepan over medium heat, melt the butter and sauté the garlic for 1–2 minutes.
Pour in the cream, bring to a gentle simmer, and stir in Parmesan cheese until smooth.
Add salt, pepper, and optional seasonings to taste.
In a large bowl, combine cooked pasta, chicken, broccoli, and half the mozzarella.
Pour the Alfredo sauce over everything and mix until coated.
Transfer to the prepared baking dish and top with the rest of the mozzarella cheese.
Bake for 20–25 minutes or until bubbly and golden on top.
Let it sit for a few minutes before serving. Try not to eat it all straight from the dish!