Roux can be many different colors depending on what you are putting it in. The darkest roux needs to be for Gumbos, spaghetti meat sauce and chili. A caramel color roux would be for soups. A blonde roux light tan would be for chicken and dumplings or something similar.
This is the proper and true Cajun/Creole way. If you like you can make larger batches to save for future dishes. I use the amount in this recipe per dish.
All you need is fat and flour in equal parts. For fat I mostly use butter or EVVO. For most of the roux that I make I use butter. NEVER use margarine!!!! NEVER!!!!
Put stick of butter in a skillet or pot that you are going to cook in and then add the flour on top. On a medium-high heat the butter will melt and then continue to stir the flour into the butter (at this point it's not a roux, just butter/flour mixed. A roux has to develop with heat, changing texture and color over time. All too many people call it a roux once it's mixed. Thats not a roux.). It will get foamy, thin, thick, foamy and thin again many times as it also changes colors. What you want to do is let it change textures at least a few times for a "blond" roux. This is a light color similar to ginger ale. Then you go to a little darker color for Etouffees and soups. Then go very dark say the color of Coke or Pepsi for Gumbos. This process takes about 20-30 minutes depending on the color you are looking for in your roux.
Make sure you continue to stir as long as this is on the fire. If you don't it will get little black flecks in it which means it's burned. If that happens you need to throw it away and start all over. It will taste like burned garbage if you don't throw it away. DO NOT STOP STIRRING. Not even for a minute!
Roux can be saved for a while in the fridge. You can make any amount that you wish by doubling the above. It's easy equal parts of flour to fat. You can also use Olive oil, peanut oil, Canola oil but Butter is the best and most rich flavor of all of them.
a picture of what a light blonde roux for dishes like sausage and gravy for biscuits and chicken and dumplings
a picture of medium roux For etouffe and light soups like chicken noodle
Then the dark roux for gumbo's, spaghetti sauce, chili, beef stew, beef soups