Ingredients
Preparation
Measure out equal amounts of butter and flour.
Dice the butter into small cubes and melt it in a saucepan over low heat.
Once the butter is melted, begin whisking in the flour.
When all the flour is incorporated, continue stirring and cooking for a few minutes to activate the starch granules.
If you plan to be making a white or light-colored cheese sauce, be sure to keep the heat low enough that the roux does not brown.
Now all you need to do is pour in the milk. If the roux is hot, the milk should be cool, but if the roux is cool, the milk should be hot. Combining the two ingredients at different temperatures ensures that they will heat up at a moderate rate–not too fast, and not too slow–ensuring a velvety-smooth sauce.
Whisk the mixture until it is smooth, then add seasonings if you wish.
Allow the sauce to simmer until it has lost its “floury” taste (this will take about 20 minutes), then strain out any seasonings.
Remove the pan from the heat and gently blend in the cheese. If the cheese doesn’t seem to be melting sufficiently, you can return the pan to very low heat, but watch it carefully and remove as soon as the cheese is melted.