1 cup (240 ml) heavy whipping cream
1 tablespoon buttermilk
Note: If possible, use pasteurized heavy whipping cream, as ultra pasteurized will take longer to thicken.
In a medium saucepan over low heat, warm the cream to 105 degrees F (40 degrees C). Remove from heat and stir in the buttermilk. Transfer the cream to a large bowl and allow this mixture to stand in a warm place, loosely covered with plastic wrap, until thickened but still of pouring consistency. Stir and taste every 6 - 8 hours. This process takes anywhere from 24 to 36 hours, depending on your room temperature. The creme fraiche is ready when it is thick with a slightly nutty sour taste. Chill cream, in the refrigerator, for several hours before using. Creme fraiche may be made and stored in the refrigerator for up to 10 days
Creme Fraiche Frosting:
In bowl of electric mixer, with whisk attachment, beat the Creme Fraiche with 1-2 tablespoons (14-28 grams) of granulated white sugar until stiff peaks form. Can be used in desserts instead of whipped cream.