1Cook the elbow macaroni according to the package instructions. Drain and set aside.
In a saucepan, melt the butter over medium heat.
Stir in the flour and cook for about 1 minute, until it forms a paste.
Gradually add the milk, stirring constantly to avoid lumps. Cook until the mixture thickens and starts to bubble.
Add the shredded cheddar cheese and grated Parmesan cheese to the sauce. Stir until the cheese is completely melted and the sauce is smooth.
Season the cheese sauce with salt and black pepper.
Add the cooked macaroni to the cheese sauce and stir until the pasta is evenly coated.
Serve the mac and cheese hot, garnished with additional cheese if desired.