Roux is an important basic ingredient in many Cajun dishes. Although it can be purchased at stores by the jar (in south Louisiana, at least), or made quickly in a microwave, the best way to prepare roux is the old-fashioned way: on the stove in a skillet. Despite the recipe's simplicity, it can take thirty minutes or longer to prepare. The key to making a good roux is to brown the flour slowly until it appears a dark copper color. But be careful — even a slightly burnt roux will ruin a dish. Although some variations exist among types of rouxs, the most common, basic recipe appears below:
1 cup all-purpose flour
¾ cup vegetable oil
Combine the oil and flour in a skillet, and stir constantly over a medium flame. The roux should begin to congeal and brown. When dark copper, like the shade of an old penny, remove the roux from the flame, and allow it to cool until warm. It now can be used as the base for a Cajun dish, such as gumbo.