To make a roux, you will need equal parts flour and butter.

Cut the butter into small, easy to melt pieces. Place the butter in a heavy-bottomed pot and melt it over low heat. Make sure that the butter only gets warm enough to melt, but not separate.

Little by little, add the equal amount of flour.

Whisk the flour into the butter until it is thoroughly incorporated.

Continue cooking over a low flame, stirring the whole time. The roux will begin to tighten after the first few minutes of cooking.

After about five minutes of cooking, the raw flour taste will begin to cook out of the roux. It will begin to emit a toasted aroma. This stage is "white roux". This stage of roux is used to thicken white sauces including Bechamel and Veloute.

The next stage of cooking will be "blonde roux". The roux will become a dark cream color and smell like toasted bread. This roux can be used to impart some flavor and thicken cream based soups and sauces.

When the roux has taken on a peanut butter color, it has become "brown roux". This is the darkest French roux. It will smell heavily toasted. This roux can be used to thicken dark soups/sauces and will impart a deep nutty flavor.

For Creole cooking, the roux can be cooked to a dark brown, melted chocolate color. This is the base for Etouffe and Gumbo.

"Red roux" is the final stage before the roux completely burns. This stage is very highly toasted to the point that it is less valuable for thickening, but used mostly for the extremely nutty flavor it imparts.