Crème Fraîche

1 cup 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. 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 crème fraîche is ready when it is thick with a slightly nutty sour taste. Chill cream, in the refrigerator, for several hours before using. Crème fraîche may be made and stored in the refrigerator for up to 10 days.