#making_white_sauce... Melt the butter in a saucepan.
**Stir in the flour and cook for 1-2 minutes.
Take the pan off the heat and gradually stir in one-third of the milk. Return to the heat and simmer, stirring, until all the milk is absorbed.
Repeat this process, stirring all the time, allowing the sauce to become thick and shiny before adding more milk.