Step 1

Put a fairly large pot over low heat. Add the butter. Melt the butter, being careful not to burn or brown it.

Step 2

Sift the flour and add it to the butter. Mix using a whisk to make a smooth, uniform mixture, known as a  roux.

Step 3

Continue cooking the roux until it is slightly golden. Continue whisking.

Step 4

Add room temperature milk to the roux, a little at a time, and mix with a whisk. Be careful not to let any lumps form. Once you have added all of the milk, bring the sauce to a boil and continue cooking to thicken it. Remove the pot from the heat and strain the béchamel if necessary.

Step 5

Add 2 pinches of salt and a grinding of both nutmeg and pepper. Stir and let cool. The béchamel should be ready to be used.
The amount of flour you use can vary depending on how thick a béchamel the recipe calls for: the more flour you use, the thicker the béchamel.