I am lactose intolerant. The worse part of this fact is that I can't have Alfredo sauce. So, I found a work-around. I make my own. It is not identical to the one served in most restaurants since it doesn't have creme, but it allows me to have something that is still really good, but won't make me sick. Once you know how to make a Béchamel sauce, you can use it for all sorts of things. It is the base of many dishes and is considered one of the 5 Mother Sauces.
I start with a Béchamel sauce to which I add shredded Parmesan Cheese.