What is a roux?
First and foremost, a roux is a sauce base or sauce thickener made from fat and flour. For our fat, we used butter. But you can technically make a roux with other animal fat solids (like bacon grease) or with fatty oils (like olive or avocado). Rouxs are important as the base for creamy sauces like a cheese sauce or a bechamel. They ensure that the sauce is nice and creamy without being lumpy or too thin. Rouxs are used often in French cooking, but “rouxs” in a general sense are used in all different styles of cooking. In Cajun cuisine, a roux is often made with bacon fat or lard rather than butter; in Japanese cooking, it is common to make a roux for yellow curry by adding yellow curry powder to the roux ingredients and cooking as usual.
How do you make a roux?
The steps to making a great roux are very simple, but I think that is what trips a lot of people up. There are really only three steps: add butter, add flour, whisk. And when we say whisk, we mean it. If you have a stainless steel pan, break it out so that you can use a metal whisk without ruining your nonstick pan. A metal whisk will be the best thing to use for a roux because it will combine the ingredients well and help ensure that there are no lumps.
I hesitate to call this a recipe, as it is essentially just three steps, so let’s call these ‘General Guidelines.’
Heat 1.5 sticks of butter over medium-low heat until melted and smooth. While butter is melted but not yet browning, slowly begin to add in 1 cup of flour, whisking as you go. Continue to slowly add flour and keep whisking quickly to ensure the flour does not clump. Once all flour is incorporated, keep whisking (you should be whisking continuously for around 20-30 minutes). What you’re looking for is a nice rich, light brown color. As your roux reaches this point, remove it from the heat but do not stop whisking until the pan has cooled to the point that you can touch it with your bare hands. If you stop whisking before the pan cools, your roux can still burn! The roux should smell nutty and toasty as the sugars in the butter caramelize and the flour toasts. These measurements should yield approximately 1 cup of roux.
Congratulations! You’ve made a roux!