Brown beef and onion. Drain fat. Stir in next 3 ingredients. Set aside.
In sauce pan, combine next 2 ingredients. Gradually stir in milk. Cook and stir over medium heat until thick. (do not boil)
Beat next 3 ingredients in bowl. Gradually stir in sauce.
Spoon Half macaroni mixture into 2-qt. oblong baking dish. Cover with meat mixture. Top with Remaining Macaroni
Bake at 325 degrees for 45 minutes or until it is set
Note: I like to serve it with broccoli spears and homemade bread or rolls.