Cook the macaroni al dente according to package instructions. Drain, rinse, and drain again. Set aside.

Place 1/2 of milk and all of the flour, pepper and mustard in a jar with a tight fitting lid. Shake until smooth, and set aside.

Pour the remaining 1 1/2 c milk into a 2 quart pot and bring to a boil over medium heat, stirring constantly. Add the flour mixture and cook, still stirring, for about 1 minute, or until thickened and bubbly. Reduce the heat to low, and add 1 1/2 c of the cheese, and stir until the cheese melts.

Remove the pot from the heat, and stir in the macaroni. Coat a 2 quart casserole dish with nonstick cooking spray and spread the macaroni mixture evenly in the dish. Sprinkle the remaining cheese over the top, and bake at 350 degrees for 30-35 minutes, or until bubbly around the edges. Remove the dish from the oven and let sit for 5 minutes before serving.

Per 1 cup serving: 232 calories, 8 mg cholesterol, 0.7 g fat, 1 g fiber, 20 g protein, 338 mg sodium