This is my mom's recipe, and for all I know, she got it from Betty Crocker. I used to love it - all but the crusty stuff on top. Now, I miss it. Note that the cheese is white Cheddar. I never knew there was such a thing as orange cheese until I was at least 10 years old, and then I became obsessed with the instant variety of mac & cheese.

Cook macaroni, rinse in cold water and drain
Alternate layers of grated sharp cheese and macaroni, covering with cheese
Beat 1 or 2 eggs and add to milk along with salt and pepper
Pour in the milk & eggs to almost (but not quite) cover
Bake at 350°F (177°C) until not too juicy - maybe 1 hour.