A roux (pronounced “roo”) is a mixture of flour and fat, and once you’ve mastered the art of making a good roux, the culinary world is at your fingertips. So many gravies, soups and sauces are at their base, a simple roux. Even macaroni and cheese requires a roux.

There are three types of roux, categorized mostly by how long you cook them. First is a white roux. This only gets cooked 2-5 minutes, and it has a lot of thickening power. Second is a blonde roux. This one is cooked for about 10 minutes and takes on a nice caramel color. Last is a brown roux, which is cooked for up to 30 minutes. You’ll want to make sure you stir it constantly so it doesn’t burn, but this is the most flavorful roux.

But more important than the length of time you cook the mixture are the ingredients. The fat you choose lies at the heart of your roux. Any good meat or poultry gravy begins with the fatty drippings from a cut of meat that you’ve cooked, but butter is also a very common fat for this process. If you’re making a “cream of” soup, you begin by sauteeing the vegetable, mushroom or meat in butter. It’s also common, especially in the south, to add milk to your roux, as you do when making gravies.