In a heavy skillet add the butter 8 ounces sharp cheddar cheese, and cream. Heat over medium-low to medium heat. Stirring constantly heat until the cheese and butter are melted and the cheese sauce is formed
In a small bowl beat the egg. Add a couple of teaspoons of the hot cheese mixture to the eggs and beat. Continue this procedure 3 to 4 more time. Then you will want to mix the egg mixture into the cheese sauce.
While making the cheese sauce cook the macaroni according to the package directions. Once the macaroni is cooked and the cheese sauce is completed add the macaroni to the cheese sauce. Mix well and continue to cook over low heat for 5 to 10 minutes.
Sprinkle the 4 ounces of cheddar cheese on top of the mac and cheese and place under the broiler. Heat until the cheese is melted and has turned slightly brown.