In a medium pot, cook the macaroni according to package directions. Drain as soon as they are al dente. Add a little oil and stir so they don't stick if you are not ready to add them to the soup right away.
Meanwhile, in a large soup pot melt the butter over medium heat.
When it is hot, add the flour and mustard. Use a whisk stir it up.
Slowly whisk in the chicken broth and half and half. Turn the heat up to medium-high, and stir constantly until the mixture comes to a low boil, about 5 minutes.
Immediately reduce the heat to low and stir in the shredded cheese.
Stir in the macaroni and ham. Keep the burner on low until it is as warm as you like.
Salt and pepper to taste.
This is great served with a big salad and bread. If you want some veggies in your soup, frozen peas make the perfect addition. Just add them with the macaroni and heat on low until thawed.