In France, the cream called crème fraîche is treated with a special culture which helps it to stay fresh longer, makes it thick and gives it a delicious, slight tang. It is an important ingredient in the light style of cooking called nouvelle cuisine, where it is used in sauces, soups and with fresh fruits.
To whip crème fraîche: Measure crème fraîche to calculate one-third of its volume. Then add this calculated amount of cold milk, water or chipped ice and a little sugar to taste, and whip until thick.