Bring the milk to a boiling point.
Melt the butter in a pot.
When it starts to crackle, add the flour at once.
Mix well with a wooden spatula or a whisk. Cook the white roux for a few minutes. Watch out not to let it brown. It must not get any coloration.
Pour the boiling milk on the cold roux.
Whisk and bring again to a boiling point. The bechamel sauce will thicken. Cook for a few minutes, stirring.
To make this recipe, some of these items will be required: