This recipe is from The Complete America's Test Kitchen TV Show Cookbook
Serves 6-8. This recipe easily divides in half.
| 1 lb | elbow macaroni |
| 4 Tbs | unsalted butter |
| 6 Tbs | unbleached all-purpose flour |
| 5 C | milk |
| 8 oz | Monterey Jack cheese, shredded |
| 8 oz | Sharp cheddar cheese, shredded |
| 1 ½ tsp | dry mustard |
| 1 Tbs + 1 tsp | salt |
| ¼ tsp | cayenne (optional) |
| 6 slices | white sandwich bread |
| 3 Tbs | unsalted butter, cold |
The oven is only used when using the topping. If so, place an oven rack at a level that will get the casserole the right distance from the broiler.
Process the bread and butter in a food processor until coarsely ground. Set aside.
Boil the macaroni in 4 qt of water plus 1 T of salt until tender.
Melt the butter in large pot over medium high heat and then add the flour, 1 tsp salt, mustard, and optional cayenne. Whisk until fragrant and it deepens in color (~1 min). Add the milk while whisking constantly. Bring the mixture to a full boil and whisk until it achieves a consistency of heavy cream (~5 min). Remove from the heat and stir in the cheeses, stirring until fully melted.
Add the cooked macaroni to the pot and cook over medium low until steaming and heated through. Transfer to an oven proof baking/serving casserole dish.
Add the optional topping to the dish and broil until the top is deep brown.