Boil pasta in salted water until it is al dente. Drain and set aside.
In a large saucepan, melt the butter. Stir in the cream of chicken soup.
Add cheese, a little at a time. Stir until smooth and then add more until all cheese has been added.
Stir in milk until incorporated. Add in sour cream, pasta, and ham (if using). Mix until completely coated.
Put on your comfy pants, fill up a big old bowl and get a spoon. This is going to be good!
Notes
For the creamiest mac and cheese, use a 12 ounce box of pasta. However, we have used a 16 ounce box several times with great results.A mild melting cheese is great for this recipe. Co-jack or Monterey Jack work great. We also like a mix of half mozzarella and half cheddar. We find using all sharp cheddar to be too strong in this recipe.