Creme Fraiche is a French-style lightly soured and thickened fresh cream, generally used as a topping or garnish for savory or sweet dishes. It can be found in small tubs in most well-stocked grocery stores or can be made at home.
To make creme fraiche:
Stir 1 teaspoon cultured buttermilk into 1 cup (8 fl oz/250 ml) heavy (whipping) cream. Cover tightly. Leave at warm room temperature until thickened, about 12 hours. Refrigerate until ready to serve. It will keep for up to 1 week.