Adapted from Cook’s Illustrated
1 pound medium shell whole grain macaroni
5 tablespoons unsalted butter
6 tablespoons all-purpose flour
1 ½ teaspoons powdered mustard
¼ teaspoon cayenne pepper
5 cups milk
8 ounces Monterey Jack cheese, shredded
16 ounces extra sharp cheddar cheese, shredded
Kosher salt to taste
Optional bread crumb topping:
6 ounces bread, torn into pieces
3 tablespoons unsalted butter (cold)
You will also need:
Food processor (if doing bread crumb topping)
Large pot or dutch oven
Broiler safe 9x13 dish
In a large pot with plenty of salted water boil shell macaroni until just past “al dente.” Drain and set aside.
Set same pot back over medium heat. Melt butter until foaming then add flour to make a roux. Cook for just a minute or so and add mustard and cayenne and whisk to combine well.
While continuing to whisk, gradually add milk; bring to a boil while whisking constantly. (It must reach a full boil to thicken, but you must keep whisking to keep it from scorching on the bottom or boiling over.) Reduce to a simmer, whisking occasionally, until thickened to a heavy cream consistency (about 5 minutes).
Remove from heat and whisk in cheeses and salt to taste. Add shells and stir to completely combine and thoroughly coat shells with cheese sauce.
If using the bread crumb topping:
Process bread and butter in food processor for 10-15 1 second pulses. Transfer shells and cheese to a broiler safe baking dish and evenly top with bread crumb topping. Broil until crumbs are deep golden brown, 3-5 minutes, rotating pan if necessary for even browning.
Allow to cool for about 5 minutes and enjoy.