Preheat and prep. Heat your oven to 375°F (190°C). Grease a 9x13-inch baking dish with olive oil or nonstick spray.

Cook the pasta. Bring a large pot of salted water to a boil. Cook pasta 1–2 minutes shy of package directions so it’s al dente. Reserve 3/4 cup pasta water, then drain.

Shred the chicken. Remove skin and bones from the rotisserie chicken. Shred the meat into bite-size pieces. You should have about 3 cups.

Make the Alfredo base. In a large skillet, melt butter over medium heat. Add garlic and cook 30–60 seconds until fragrant, not browned.

Build the sauce. Stir in heavy cream and bring just to a gentle simmer. Add cream cheese in small pieces, whisking until smooth.

Add Parmesan and seasonings. Off the heat, whisk in Parmesan until melted. Season with salt, black pepper, Italian seasoning, and red pepper flakes if using. If the sauce seems too thick, whisk in 1/2 cup pasta water or broth, adding more as needed for a pourable consistency.

Toss everything together. In a large bowl, combine the drained pasta, shredded chicken, and the sauce. Stir to coat evenly. Taste and adjust seasoning.

Assemble the bake. Transfer the mixture to the prepared baking dish. Top evenly with mozzarella and a light sprinkle of extra Parmesan.

Bake. Cover loosely with foil and bake for 15 minutes. Remove foil and bake another 10–12 minutes until the top is melted and lightly golden around the edges.

Rest and garnish. Let the bake rest 5–10 minutes to set. Sprinkle with chopped parsley before serving.