Start by combining the cream and buttermilk in a glass jar or resealable container.
Next, mix the ingredients together until they are well blended, before sealing the container and allowing it to sit at room temperature for 12-24 hours.
Once this time has passed, your crème fraîche mixture should have thickened into a creamy texture.
It can then be stored in the refrigerator for up to 10-12 days.
For best results, try stirring in some freshly chopped herbs or spices before serving to add an extra layer of flavor to your dish, or use it as described in the recipe you are following.
Notes
Make sure to use heavy cream when creating crème fraîche, as this will help ensure that the mixture thickens properly.
Letting the crème fraîche sit out for 12-24 hours is essential, but if you'd like a richer flavor don't hesitate to let it sit out for an additional 4-8 hours.