I make a large batch using a 4 cup Pyrex measuring cup with handle. Any microwave glass dish will work, remember to use oven safe mits when grabbing it will be hot! Mix oil and flour in dish until well incorporated. I don't measure, most people use a 1:1 ratio or whatever you prefer. I usually add 2 c flour in my dish and add oil till consistency is right. Microwave for 5 mins. (less time if Making a small amount)

Remove HOT DISH from microwave. Place on pot coaster (protect your counter) mix well, place back into the microwave 2-3 min increments, remove, stir, repeat until desired darkness achieved.

Mixture will be HOT and will continue cooking as the oil is bubbling even after microwave is off. I stop cooking a bit before desired darkness mix and let it sit until cooled. You will notice the center is usually darker than the outside. This is why we mix it in each time.

You will get the hang of this with your microwave with time. I make a large batch and store the cooled roux in a jar for adding to stews and Gumbo or making a Gravy with meals. Oil will rise to the top when cooled, you can pour it off, mix it in, or use it to saute veggies.

How to mix roux to make gravy: I add about 1-2 tbs to a cup of warm water, meat drippings, or broth and whisk well until a paste forms then add to my stew (the rest of meat drippings, liquid in the pot) Use more or less if desired depending on how big your meal is.