• Preheat oven to 350°F (175°C). Grease a 9x13-inch baking dish or two 8x8-inch or 9x9-inch baking dishes if you plan to freeze one for later.
• Season chicken breasts lightly with salt and pepper if desired and bake for 25–30 minutes, or until cooked through (165°F internal temperature). Let cool slightly, then cut into bite-sized pieces. (Or use about 3 cups of cooked shredded chicken.)
• While the chicken bakes, cook the pasta in a large pot of salted boiling water until just shy of al dente (1–2 minutes less than package directions). Drain well.
• In a large bowl, combine the cooked pasta, chopped chicken, Alfredo sauce, garlic salt, Italian seasoning, and shredded cheese. Stir until everything is evenly coated.
• Spread the mixture into the prepared baking dish (or divide between two smaller dishes). Top with extra shredded cheese if desired.

To bake now:

• Cover the casserole loosely with foil and bake at 350°F for 20 minutes. Remove the foil and bake an additional 5–10 minutes, or until the casserole is hot and bubbly and the cheese on top is melted.

To freeze and bake later:

• If freezing, let the assembled casserole cool to room temperature. Wrap tightly in plastic wrap and then in foil. Label with the name and date, and freeze for up to 2–3 months.
• To bake from thawed, thaw in the refrigerator overnight. Remove plastic wrap, cover with foil, and bake at 350°F for 25–35 minutes, or until hot and bubbly. Remove foil for the last 5–10 minutes to brown the cheese.
• To bake from frozen, remove plastic wrap, cover with foil, and bake at 350°F for 60–75 minutes, or until the center is hot and the sauce is bubbling around the edges. Remove foil for the last 10–15 minutes to melt and lightly brown the cheese.