Macaroni and Cheese

This is from Cook's Illustrated. The only thing I would do differently would be to experiment with a different crunchy crust. This one tasted a little too much like bread, so I would probably top it with a mixture or more shredded cheese and pre-fab bread crumbs and butter. But I am posting this in its original form and welcoming suggestions.

TOPPING
6 slices white bread, torn into pieces
3 T cold unsalted butter, cut into 6 pieces

MAC AND CHEESE
1 pound elbow macaroni
Salt
5 T unsalted butter
6 T all-purpose flour
1 1/2 t dry mustard
Dash cayenne if you want
5 c milk
8 oz Monterey Jack cheese, shredded (2 cups)
8 oz sharp cheddar cheese, shredded (2 cups)
(Note on the cheese: Pre-shredded cheese usually is treated with some anti-caking agent and can impact the loveliness of the mac and cheese. It's better to grate your own, even though that sucks.)

1. FOR THE TOPPING: Pulse the bread and butter in a food process until the crumbs are no larger than 1/8 inch, ten to fifteen 1-second pulses. Set aside.

2. MAC AND CHEESE: Cook the macaroni per package directions until just tender (so if it says 6-8 minutes, cook for six). Drain and set aside.

3. In the pot you cooked the macaroni in, heat the butter over medium-high heat until foaming. Add the flour and mustard (and cayenne if you want) and whisk well to combine. Keep whisking for about 1 minute. Whisking constantly, gradually add the milk. Bring it all to a boil, whisking constantly (and turn it up a little if you have to - it has to come to a full boil to thicken properly). After it boils, reduce the heat and cook for about five minutes, whisking occasionally, until the mixture has the consistency of heavy cream. Take the pot off the heat and whisk in the cheeses and 1 t salt until the cheese are fully melted. Add the pasta and cook over medium-low heat, stirring constantly, until the mixture is steaming and heated through, about 6 minutes.

3. Put the pasta and cheese in a casserole dish and top with the bread crumbs. Stick it under the broiler until the crumbs are crispy and brown and delicious. Let stand for five minutes and then serve.

- jenny