At your cook top turn the heat on high, place your pot on the burner and put in the oil and flour. Stir until this is mixed well. When the oil and flour start to bubble stir constantly for 5 minutes then turn your heat to down to medium high. Keep stirring.

In a few minutes the flour will start to darken. When you see a caramel color developing turn the heat down to medium. Keep stirring using your spatula or whisk taking care to scrape every part of the pot bottom. Don't stop. Relax. A traditional roux takes a little time.

The next image shows the roux beginning to turn color. This is the first stage and is your confirmation the roux is progressing well.

After a little more stirring you will see the flour getting browner. Keep stirring. Maintain the medium heat setting. A high heat will burn. Trust me on this. Your goal is to get the roux browned to the color of milk chocolate or an old copper penny. I have taught many people how to get a correct color. To help demonstrate the color stages I will have a jar of peanut butter out to compare to the roux to show phases of color. When the roux reaches a color of peanut butter it is about half way done.

Keep on stirring as the roux continues to darken. To get the best Cajun style gumbo the color needs to be darker brown.

At this color stage I recommend a low heat setting. This allows you to maintain control of the darkening process without the risk of burning. You will probably see a slight amount of smoke rising from the pan and this is normal. Just turn on your vent to remove the smoke. Keep going, keep stirring and soon enough your roux will start approaching that red brown or milk chocolate color stage that is so important. When your roux is red brown or the color of milk chocolate put in the diced vegetables. When the onions, green pepper and celery (known as the trinity) go into the roux there will be a lot of hissing and steaming. This is normal. Use your spoon to stir and blend in this mixture. Keep the heat on low. Keep stirring and scrape the bottom of the pot. Soon the vegetables will start to get transparent and the roux will get darker. Don't worry about the darker color at this point. This is due to the moisture and sugar in the vegetables and does not mean the roux is burning. In fact the entire mixture should be real dark after about 10 minutes of cooking on low heat. At this point the traditional roux and vegetable mixture is ready. You can add your stock and seasonings here or if you want to finish the gumbo later you can turn off the heat and come back. This mixture will freeze well for future use.