Crème Fraîche is hard to find and is incredibly expensive. This will show you how easy and inexpensive it is to make.
Combine cream and buttermilk in a jar or other non-reactive container. Cover with a piece of cheesecloth secured with a rubber band. Let sit at room temperature, around 70° F for 12 to 24 hours, or until thickened.
Stir to combine. Transfer to a covered container and refrigerate. (See Note 2)
Yield: 1 cup and 2 tablespoons.