Melt 2 tablespoons butter in a saucepan over medium heat
Add 2 tablespoons all-purpose flour
Whisk constantly for 1 to 2 minutes to form a smooth paste
Gradually pour in 1 cup milk while whisking continuously
Keep whisking until the sauce is smooth and starts to thicken
Cook for 3 to 5 minutes, stirring often
Season with salt and pepper
Remove from heat and use immediately