You want this. Franklin wanted this.
6 T Butter
6 T Flour
4 cups milk, plus
4 cups mild cheddar
1 cup gruyere or fontina
2 cups parm, pecorino, or romano (or the handy three-blend at your local uber-store)
1 lb large elbow macaroni (you know the drill, sub whatever you want)
Cook the noodles by the book.
While that's going on, medium heat y'all. Melt the butter in a large sauce pan. Add the flour. Whisk for a few seconds (60-ish). Add the milk and keep stirring.
Add the gruyere/fontina by handfuls and stir until incorporated. Add 3 cups of the cheddar in batches while stirring. Add 1/2 cup of the parm/pecorino/romano.
Drain the noodles, put them in a 9/13 pyrex. If you don't have one, tell your roommate to stir the cheese sauce while you go get one.
Pour the cheese sauce over the noodles. Stir through so the noodles are all coated.
Admire the awesome fury of your creation. (Remember the feeling, it'll only get better).
Throw the last cup of cheddar and the rest of the hard cheese on top evenly.
You did preheat to 375, didn't you? Good. Put it in the oven for 40 minutes.
Pull it out.
Admire the awesome-er fury of the crusty-cheesy goodness.
Trusy me here. Let it cool for at least a few minutes. Unless you're putting it in a bowl. Cause really, when it's that hot and bubbly, it's still just mac n' cheese soup.
I usually add some dry mustard powder to the roux. Sometimes a dash of nutmeg too. Go REAL EASY on the nutmeg if you try that. Both add a depth of flavor that takes it over the top. I had neither tonight. C'est la fromage.