ROUX
Weigh out 2oz of flour (cake or pastry flour is preferable to all-purpose but all-purpose works just fine) and 2oz fat, bacon, butter, or other.
Heat the butter and then add the flour, whisking as you go. Make sure all the flour is covered with the fat. On low to medium heat, use either the stovetop or oven to cook the roux for at least 10 minutes. The longer you cook the roux the more nutty flavor it will develop, like 30 min, 45 min. Stir regularly to avoid burning.
Use cold roux to thicken stocks or soups for gravy.
Or use to make an all-purpose white Bechamel Sauce, the basis for cream and cheese sauces.
BECHAMEL SAUCE
The Roux recipe above and 1 cup of room temperature milk.
Heat the Roux in a fry pan.
Remove the hot roux from the heat and add the warm milk in a steady, thin stream, whisking out any lumps as you pour.
Alternatively, add about 1/3 cup of milk and whisk vigorously until the milk has been completely absorbed by the Roux and repeat until milk is all absorbed by the sauce.
C’est ca.