Bring a saucepan to a boil. Add macaroni, and cook until not quite done, about 6 minutes.
In a separate saucepan, melt the butter over medium heat. Mix in the flour, mustard powder, and pepper until smooth. Slowly stir in the milk. Add in the cheese, and stir constantly until the sauce is thick and smooth.
Drain noodles, and stir them into the cheese sauce. Serve while warm
The nutrition information provided are only estimates based on an online nutritional calculator. This is not a comprehensive list of all the nutrients in the recipe (i.e., does not include vitamins, cholesterol, etc). I am not a certified nutritionist. Please consult a nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have.