Crème Fraîche

Crème fraîche should be started at least 48 hours in advance, as the thickening time varies, and for many recipes the cream needs several hours of chilling before use. Some chefs use sour cream instead of buttermilk. More sour cream per cup of heavy cream is required to start the culture, so the resulting crème fraîche is not as rich and will not whip as beautifully.