Barely Adapted from EzraPoundCake.com
Serves 3 to 4 as a main course
1 1/2 cups (6 ounces) grated extra-sharp cheddar
1 cup (4 ounces) grated Monterey Jack
1/2 cup (2 ounces) grated Gruyere
2 1/2 cups milk
3 tablespoons unsalted butter, plus more for the dish
3 tablespoons all-purpose flour
1 teaspoon ground mustard
1 teaspoon kosher salt
1/4 teaspoon freshly ground black pepper
1/8 teaspoon freshly grated nutmeg
Dash of cayenne
1/2 pound (8 ounces) elbow macaroni
1. Preheat the oven to 375 degrees. Set a baking rack in the top-third of the oven. Butter a 1 1/2 quart casserole dish (or an 8″-by-8″ baking dish). Set aside.
2. Combine the cheddar, Monterey Jack and Gruyere cheeses in a medium bowl. Transfer 1 cup of cheese to a small bowl; reserve for topping.
3. In a medium saucepan, warm the milk over medium heat.
4. In a Dutch oven or saucepan set over low heat, melt the butter. Add flour immediately; whisk to combine for about 1 minute. Raise the temperature to medium, and slowly whisk in the milk. Bring it to a boil to thicken, whisking the entire time. (You might need to raise the temperature slightly to get things going.)
5. Remove the pan from the heat. Stir in the mustard, salt, pepper, nutmeg, cayenne and the 2 cups of mixed cheeses (from the larger bowl). Set the cheese sauce aside.
6. Fill a large saucepan with water, and bring it to a boil over high heat. Add macaroni. Return the water to a boil, and cook for about 10 minutes. Drain well, and add pasta to the cheese sauce. Stir to combine. Taste, adjust the seasonings, and add hot sauce, if you wish.
7. Transfer the mixture to the prepared baking dish. Top with reserved cheese, and bake in the top-third of the oven for about 25 minutes, until the top is golden brown and bubbly, but the inside is still creamy.