Cook the macaroni in boiling, salted water until tender. Meanwhile, combine the flour and 1 cup of the heated milk in a small glass jar. Screw on the lid tightly and shake until the milk and flour are completely blended. Pour into a heated saucepan and stir in the remaining cup of warm milk. Stir constantly over medium heat until the sauce boils and thickens. Stir in the pepper and salt to taste. Add the cheese and continue cooking and stirring until the cheese is melted. Drain the macaroni and add to the sauce. Stir to coat. Heat thoroughly, stirring. Serves 5.