Boil water and a dash of salt in a large pot and cook your pasta until al dente.
While your noodles boil, shred your cheeses.
Drain your noodles, then pour them into a 9x13 casserole dish.
Melt your butter on medium high heat in a large pot, or deep skillet.
Whisk your flour into the melted butter to create a roux. Whisk until there aren't any lumps.
Pour your milk in whisking as you add it. If your roux isn't thickening, increase the heat and keep whisking.
Keep whisking until the “gravy” thickens up a bit. If it gets too thick add a splash of milk at a time until it’s at your desired consistency. We're going for the consistency of your basic white gravy.
Throw half of your cheese into the mix and whisk until it melts and becomes “cheese gravy”.
Pour your cheese gravy over the noodles in the casserole dish, and mix it all together.
Sprinkle your remaining cheese over the top and put it in the oven.
Bake for 15-20 minutes, or until cheese is melted and bubbling. Don't overcook or the cheese will get greasy.
Try the following variations to mix it up:Top with fried onions.Add bacon!Melt some butter in a skillet and add bread crumbs, toss 'em around and throw those on top of the mac and cheese before baking.More cheese - my favorite. Try adding some gruyere cheese in with the cheddar, so good.Grab all of your favorite cheeses and throw them in there.Use those super fun spiral noodles (cellentani noodles).