Throw the flour into the loaf pan. Smooth-out the lumps with a butter knife. Pour in the oil and stir with a small whisk. Set the timer on the microwave for 18 minutes and cook control to 50%. Start the microwave. At 45 seconds to 1 minute intervals, stop, whisk the roux and restart the microwave - until the roux becomes the color of light chocolate. From this point on, stop, whisk the roux and restart the microwave at 25 second intervals - until the roux becomes dark chocolate brown. Remove the roux from the oven and stir - periodically - until cool. The residual heat should turn the roux to a brick color.
The above, microwave method of roux-making should take 15-18 minutes to achieve a dark (chocolate) roux - a shorter time period than making a roux with a wooden spoon over low heat but longer (and less dangerous) than making a roux with a whisk over high heat.
