A lovely blend of cheeses and pasta topped with buttery bread crumbs
Pulse bread and butter in food processor till crumbs form, about 10-15 pulses. Set aside.
Add macaroni and 1 tablespoon salt to a large pot of boiling water. Cook until pasta is tender (not al dente; it should be fully cooked). Drain pasta and set aside.
In the same pot you used to boil the pasta, heat butter till it gets foamy.
Add flour, mustard, and cayenne and whisk well to combine.
Continue whisking until the flour mixture browns slightly, about 1 minute.
Slowly whisk in milk and bring mixture to a boil, whisking constantly until the sauce starts to thicken. Reduce heat and whisking occasionally, let the sauce thicken to the consistency of heavy cream. Remove from heat and whisk in cheese along with the 1 teaspoon salt. When cheese is melted, stir in pasta and cook till mixture is fully heated through, about 5 minutes.
Add the pasta mixture to greased 9 x 13-inch baking dish, sprinkle with bread crumbs if using. Broil until the topping is golden brown, about 3-4 minutes. If not using the topping, place casserole under the broiler until the top browns slightly. Sprinkle with paprika for color. Cool about 5 minutes before serving.
Adapted from Cook’s Illustrated.
Alternatively, you can saute the bread crumbs in butter until browned to top the macaroni and cheese. Place in a 350º oven to heat for 10 minutes before serving.