Mie means the crumb and also very soft white bread or pain de mie, made with a bit of sugar and sometimes butter; while it’s occasionally sold in boulangeries, it’s a supermarket sandwich bread staple, sold sliced in a variety of styles from white to whole grain.
It’s essential for making a croque monsieur. It is the bread twice baked to make biscottes.
Some people wad it into balls to clean dirty paintings.
Image by Bryan Alexander