8 tablespoons unsalted butter ( plus more to butter casserole dish
6 slices good white bread, crusts removed, torn into 1/4 to 1/2 pieces
5 1/2 cups milk
1/2 cup all purpose flour
2 teaspoons salt ( plus a little more for water )
1/4 teaspoon freshly grated nutmeg
1/4 teaspoon ground pepper
4 1/2 cups ( about 18 ounces ) grated sharp white cheddar cheese
2 cups ( about 8 ounces ) grated Gruyere cheese
1 pound elbow macaroni

8 tablespoons unsalted butter ( plus more to butter casserole dish 6 slices good white bread, crusts removed, torn into 1/4 to 1/2 pieces 5 1/2 cups milk 1/2 cup all purpose flour 1/4 teaspoon freshly grated nutmeg 1/4 teaspoon ground pepper 4 1/2 cups ( about 18 ounces ) grated sharp white cheddar cheese 2 cup s ( about 8 ounces ) grated Gruyere cheese 1 pound elbow macaroni

1) Preheat oven to 375. Butter a 3 quart casserole dish; set aside. Place bread in a medium bowl. In a small saucepan over medium heat, melt 2 tablespoons butter. Pour melted butter into the bowl with the bread; Set the bread crumbs aside.

2) Warm milk in a saucepan over medium heat. Melt remaining butter in a high-sided skillet over medium heat. When butter bubbles, add flour. Cook, whisking, 1 minute.

3) While whisking, add hot milk a little at a time to keep mixture smooth. Continue cooking, whisking constantly, until mixture bubbles and thickens, 8-12 minutes.

4) Remove pan from heat. Stir in salt, nutmeg, pepper, 3 cups cheddar cheese, and 1 1/2 cups Gruyere; set the cheese sauce aside.

5) Cover a large pot of salted water, and bring to a boil. Cook the macaroni until the outside of pasta is cooked and the inside is underdone, 2-3 minutes. Transfer the macaroni to a colander, rinse under cold running water, and drain well. Stir the macaroni into the reserved cheese sauce.

6) Pour mixture into prepared dish. Sprinkle cheddar and Gruyere and bread crumbs over the top. Bake until golden, about 30 minutes.

7) Transfer dish to a wire rack for 5 minutes.