Honey & Haycorns' Smitten Kitchen's Martha Stewart's Macaroni and Cheese

6 tablespoons unsalted butter, plus more for casserole
5 1/2 cups milk
1/2 cup all-purpose flour
2 teaspoons coarse salt, plus more for water
1/4 teaspoon ground nutmeg
1/4 teaspoon freshly ground black pepper
1/4 teaspoon cayenne pepper
4 cups (about 16 ounces) grated sharp white cheddar cheese
1 pound elbow macaroni

Heat oven to 375°F. Butter a 3-quart casserole dish; set aside.

Warm the milk in a medium saucepan over medium heat. Melt the remaining 6 tablespoons butter in a high-sided skillet over medium heat. When the butter bubbles, add the flour. Cook, stirring, 1 minute.

While whisking, slowly pour in the hot milk a little at a time to keep mixture smooth. Continue cooking, whisking constantly, until the mixture bubbles and becomes thick, 8 to 12 minutes.

Remove the pan from the heat. Stir in salt, nutmeg, black pepper, cayenne pepper, and 3 cups cheddar cheese; set the cheese sauce aside.

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, 4 to 5 minutes. Transfer the macaroni to a colander, rinse under cold running water, and drain well. Stir the macaroni into the reserved cheese sauce.

Pour the mixture into the prepared dish. Sprinkle the remaining 1 cup cheddar cheese over the top. Bake until golden brown, about 30 minutes.  Transfer the dish to a wire rack for 5 minutes; serve.

Serves 12.

From Martha Stewart Living Cookbook: The Original Classics via Smitten Kitchen blog, with changes