Melt 2 tablespoons butter in a skillet over medium heat
Whisk in 2 tablespoons all-purpose flour
Cook for 1 to 2 minutes, whisking constantly
Slowly pour in 1 to 2 cups milk while whisking
Continue whisking until smooth and thickened
Add salt and black pepper to taste
Simmer for 2 to 3 minutes, stirring often
Serve warm