What is it?  Slightly soured heavy cream.

What does it taste like?  At first, more like cream than sour cream, only thicker.  As it gets older, it tastes more like sour cream.

What do you do with it?  The same things you’d do with sour cream or plain yogurt in cooking; the difference is that you can heat creme fraiche and it won’t separate.

How do you make it? Add 2 T buttermilk to 2 c cream, leave on the counter for a few hours or until it’s a pudding consistency, and then put it in the fridge.  Simple as hell.