Preheat the oven to 350 degrees. Cook macaroni according to package directions, drain and set aside.
Saute the onion in the butter for 3 minutes, or until onions are softened.
Whisk in th flour and cook for 2 minutes or until the flour and butter mixture is bubbly and brown.
Slowly whisk in the milk and continue to whisk until mixture begins to thicken. Add the cheese and stir until melted.
Stir in the cooked macaroni and transfer to a baking dish. Sprinkle the bread crumbs evenly over top.
Bake in the oven for 25 minutes or until bubbly and top begins to brown.
Notes
Tips and Substitutions
Make sure to cook the butter and flour mixture for the amount of time indicated. When doing so, it is cooking the rawness out of the flour, adding to the nuttiness of the butter as it browns.
Use your favorite of any of these cheeses: cheddar, monterey jack, colby, pepper jack, american, and gouda.
Use crushed saltine or buttery round crackers to top the macaroni and cheese instead of the Italian bread crumbs
Stir in a cup of diced ham or try a cup of cooked shrimp or lobster!
Use any type of milk you prefer. Skim, reduced-fat, whole or even your favorite nut milk.