Melt 2 tablespoons butter in a saucepan over medium heat
Add 2 tablespoons all-purpose flour
Whisk continuously for 1 to 2 minutes to form a smooth roux
Gradually pour in 1 cup milk while whisking constantly
Continue whisking until the sauce is smooth and begins to thicken
Cook for 3 to 5 minutes, stirring often, until desired consistency is reached
Add salt and black pepper to taste
Remove from heat and use immediately