Cook the pasta according to the package instructions. Drain well.
Melt the butter in a saucepan over medium heat. Whisk in the flour and stir for about 1 minute until bubbly and golden brown.
Gradually whisk in the milk until smooth. Add in the cheese's, stirring often, bring to a simmer. Once the sauce starts to thicken, continue whisking until it is smooth and there are no lumps. The sauce should be thick and creamy.
Stir in the pasta until it is fully coated with the cheese sauce. Season with salt and pepper to taste before serving.