If you don't know how to make roux, learn today! It's the starter for the best mac and cheese, clam chowder, white sauce...
I totally borrowed much of this from Taste of Home (https://www.tasteofhome.com/article/how-to-make-roux/); it's a reliable source and they spell it out nicely.
Types of Roux
- White roux is the most common and it has the most thickening power. You’ll find it in recipes for white sauce (also called bechamel) and soups. You only cook the roux long enough to eliminate the flour’s raw flavor, about 2 to 5 minutes.
- Blonde roux is caramel colored and has a nuttier flavor. It is cooked for about 10 minutes. You would use this type of roux to make velouté (one of the mother sauces) but you can also use it in any recipe that calls for a white roux.
- Brown roux is the darkest. It’s cooked for as long as 30 minutes, and you’ll want to stir it constantly to keep it from burning. You’ll also find that many cooks use vegetable oil instead of butter for these types of roux. You’ll end up with a maple-colored mixture that doesn’t have as much thickening power as the other two types, but it is deeply flavorful. Use this roux for Cajun dishes like gumbo.
Source: https://www.tasteofhome.com/article/how-to-make-roux/
Ingredients
2 tablespoons butter*
2 tablespoons all-purpose flour
1/8 teaspoon salt (opt.)
Dash white pepper (opt.)
*Vegetable oil may be used if making a dark roux; it has a higher smoking point and can handle the longer cooking time.
Directions
Step 1: Make a white roux
All roux starts with a white roux—cooking the roux just long enough to eliminate the taste of raw flour. In a small saucepan, melt the butter (or oil) over medium heat. Add the flour, salt and pepper and stir with a rubber spatula, mixing until they’re well combined and the mixture looks smooth. Cook, stirring frequently, for 2 minutes, until the mixture is bubbly and foamy. At this point, it should look like a thick paste.
Taste of Home Pro tip: Most roux recipes instruct you to use a whisk, but I like using a rubber spatula. It helps you get into the corners of the saucepan, making sure the mixture doesn’t collect and burn there.
Step 2: Keep it going for a blonde roux
To deepen the nutty flavor of your roux, continue cooking it for as long as 10 minutes, stirring frequently. This will weaken the thickening power of the flour, but it will turn an appealing caramel color and add a huge amount of flavor to any dish.
Step 3: Cook even longer for a brown roux
For a brown roux, keep going for another 20 minutes, cooking the roux as long as 30 minutes total. It will turn out deep and rich with a nuttier flavor and aroma. It’s reminiscent of brown butter with an almost smoky quality.
Enjoy!
Step 4: Use it or save it for later
Use your prepared roux as the foundation for any number of dishes, either immediately or over time. To use the roux immediately, whisk in 1 cup of cold milk or broth. Bring the mixture to a boil and cook for about 2 minutes, stirring with a rubber spatula, until the liquid is nice and thick. You can easily create a cheese sauce from here by adding shredded cheese—perfect for pouring over potatoes, vegetables or as the base for macaroni and cheese.
Roux also stores exceptionally well. Store it in an air-tight container in the refrigerator for up to 6 months, or freeze it for up to a year. You can place dollops on a sheet pan and put them into a freezer bag once they’re frozen, or freeze your roux in ice cube trays.
Pro tip: To prevent lumps when adding liquids to a roux, always add cold liquid to hot roux (or, cold roux to hot liquids). If both the roux and the liquid are hot, the mixture will clump up quickly and you’ll end up with lumps.
Now that you know how to make a roux, add it to pan drippings from roasts to create an easy gravy or sauce to complete a delicious dinner!
Credit
I want to be sure and give full credit for this post. I've been making a roux for many years at the start of a bisque or my homemade macaroni and cheese but when researching if I can freeze roux found this great resource.