tablespoons of butter over medium heat. Once melted and just beginning to foam, sprinkle in the 4 tablespoons of flour.
Whisk the flour and butter together to form a smooth paste (a roux). Cook this mixture for 1–2 minutes, stirring constantly, to remove the raw flour taste. It should stay pale and smell slightly nutty, not browned.
Slowly pour in the milk, a little at a time, whisking constantly to keep the sauce smooth. At first it will look lumpy, but as you continue to add milk and whisk, it
