Bread Crumb Topping
Pasta and Cheese
- 6 slices good-quality white sandwich bread (~6oz), torn into rough pieces
- 3 T unsalted butter (cold), cut into 6 pieces
- 1 lb elbow macaroni
- 1 T table salt
- 5 T unsalted butter
- 6 T all-purpose flour
- 1½t powdered mustard
- ¼ t cayenne pepper (optional)
- 5 c milk (see note)
- 8 oz Monterey Jack cheese, shredded (2c)
- 8 oz sharp cheddar cheese, shredded (2c)
- 1 t table salt
- Pulse bread and butter in food processor until crumbs are no larger than 1/8 inch, ten to fifteen 1-second pulses. Set aside.
- Adjust oven rack to lower-middle position and heat broiler.
- Bring 4 quarts water to boil in Dutch oven over high heat. Add macaroni and 1 tablespoon salt; cook until pasta is tender. Drain pasta and set aside in colander.
- In now-empty Dutch oven, heat butter over medium-high heat until foaming.
- Add flour, mustard, and cayenne (if using) and whisk well to combine. Continue whisking until mixture becomes fragrant and deepens in color, about 1 minute.
- Gradually whisk in milk; bring mixture to boil, whisking constantly (mixture must reach full boil to fully thicken).
- Reduce heat to medium and simmer, whisking occasionally, until thickened to consistency of heavy cream, about 5 minutes.
- Off heat, whisk in cheeses and 1 teaspoon salt until cheeses are fully melted.
- Add pasta and cook over medium-low heat, stirring constantly, until mixture is steaming and heated through, about 6 minutes.
- Transfer mixture to broiler-safe 9-by 13-inch baking dish and sprinkle evenly with bread crumbs. Broil until crumbs are deep golden brown, 3 to 5 minutes, rotating pan if necessary for even browning. Cool about 5 minutes, then serve.