The traditional Southern way is to add chicory to a rich dark roasted coffee bean to make a thick espresso. Then heat whole milk until hot, but not boiling. When the skin forms, whisk the milk until it bubbles, then mix equal parts of the espresso and foamy hot milk, For a sweeter Cafe au Lait you can use sugar in the coffee,or use half and half instead of whole milk.
Because I am vegetarian, I use the above with unsweetened soy, it heats and bubbles just as well as the whole milk and I find it just as pleasing.
Cafe au Lait is divine with a bit of dark chocolate or a rich chocolate desert, and it is a flawless finish to a spicy dish like Gumbo.