Cook pasta in a large pot of boiling salted water for 1–2 minutes less than indicated on the package. Prior to draining pasta, remove about ½ cup of the cooking liquid and set aside.
Drain pasta well then immediately return to pan. Stir in butter, Parmesan cheese and garlic salt. Stir in a small amount of reserved pasta water, loosening pasta to desired consistency. If you forgot to reserve some of the pasta water before draining, just use a little milk.
Add pepper to taste then stir until sauce becomes nice and creamy. Serve immediately and enjoy.
One Last Thing
Why make the boxed stuff when you can make a yummy dish using ingredients you already have in the pantry?