Cook the macaroni in lightly salted boiling water for about 10 minutes, until tender but still firm. Drain well and set aside.
Preheat the oven to 400┬║F. In a deep skillet, melt the butter over medium heat. Add the flour to make a roux and cook, stirring constantly, to remove any lumps. Pour in the milk and cook until the mixture is thick and smooth, still stirring all the while. Stir in 4 cups of the Cheddar and continue to cook and stir until the cheese melts. Season with salt and pepper. Add the cooked macaroni and fold to incorporate. Transfer the macaroni mixture to a 3-quart baking dish. Sprinkle the top with the remaining cup of shredded cheese. Bake for 30 minutes, until hot and bubbly.
Edited: October 14th, 2009