How to Make It
Melt butter in a heavy saucepan over low heat; whisk in flour until smooth. Cook, whisking constantly, 1 minute. Gradually add milk; cook, whisking constantly, over medium heat until thickened. Whisk in salt and pepper.
Melt butter in a heavy saucepan over low heat; whisk in flour until smooth. Cook, whisking constantly, 1 minute. Gradually add milk; cook, whisking constantly, over medium heat until thickened. Whisk in salt and pepper.