Heat the milk in a 2 cup or larger microwavable measuring cup for about 90 seconds. Do not let the milk come to a boil. The milk can also be warmed over low heat in a small saucepan.
In a medium saucepan, melt the butter.
Stir the flour into the melted butter, stirring constantly for about 2 minutes.
Slowly add the hot milk and bring to a boil; stirring constantly.
Remove from the heat, add the salt, pepper, and nutmeg as desired, and serve immediately.
For a deliciously creamy cheese sauce, stir in any type of cheddar cheese you like until it’s completely melted and smooth.