Crème fraîche, a rich and slightly tangy cream used in pastas, soups and baked fruit desserts, is not stocked in every grocery store and can be costly where it is sold. A home version requires only two ingredients and time.
Combine one cup of room-temperature heavy or whipping cream with two tablespoons of buttermilk in a glass jar and cover it. Let the jar stand at room temperature for 8 to 24 hours, or until the mixture thickens. Stir well, then refrigerate for up to two weeks.
The method relies on the cultures in buttermilk to thicken the cream without added stabilizers. Room temperature is the only condition specified; the source does not give a narrower range or note altitude adjustments. The 8-to-24-hour window allows for variation in kitchen temperature and desired thickness, and the two-week refrigerator life applies after the initial fermentation. No salt, sugar or other flavorings are included in the source instructions.
Editorial Notes