Bring 2 1/2 quarts water to a boil in a large saucepan. Stir in 2 teaspoons salt and the macaroni; cook until the pasta is completely cooked and tender, about 5 minutes. Drain the pasta and leave it in the colander; set aside.

To the now empty saucepan, add the evaporated milk, 1/2 cup of the 2 percent milk, mustard, garlic powder (if using), cayenne, and 1/2 teaspoon salt. Bring the mixture to a boil, then reduce to a simmer. Whisk the cornstarch and remaining 1/4 cup milk together, then whisk it into the simmering mixture. Continue to simmer, whisking constantly, until the sauce has thickened and is smooth, about 2 minutes.

Off the heat, gradually whisk in the cheddar until melted and smooth. Stir in the macaroni, and let the macaroni and cheese sit off the heat until the sauce has thickened slightly, 2 to 5 minutes, before serving.

PER SERVING: Cal 360; Fat 10 g; Sat fat 6 g; Chol 40 mg; Carb 45 g; Protein 24 g; Fiber 1 g; Sodium 720 mg