Bring a large pot of lightly salted water to a boil. Cook elbow macaroni in the boiling water, stirring occasionally until cooked through but firm to the bite, 8 minutes.
2.At the same time, melt butter in a saucepan over medium heat. Add flour, salt, and pepper and stir until smooth, about 5 minutes. Pour in milk slowly, while stirring continuously. Continue to cook and stir until mixture is smooth and bubbling, about 5 minutes, making sure the milk doesn't burn.