Roux– A paste used for thickening sauces, made from equal parts of fat and flour

Stephanie Lim(2017)What is…..Roux?

Quote from a article–A roux is a smooth paste, made from flour fried in fat, that is added to sauces, soups or gravy to make them thick, smooth and rich. The invention of the technique in the 17th century.

My thoughts– Ive never heard about this mixture, when I become a chef, I would like to see if this substance can help me thicken a sauce when I need it to be.I have to be weary to not make the sauce to heavy since it has butter.