Homemade Creme Fraiche

Directions

1. 1
   You'll want to seek out a good quality heavy cream that is pasteurized, not ultra-pasteurized. If you can only find ultra-pasteurzed, it will work, but will take longer to thicken.
2. 2
   To start, you want to pour 1 cup of heavy cream into a non-reactionary container (basically, any container that isn't made from iron or aluminum).
3. 3
   Next, add two tablespoons of buttermilk to the heavy cream. Cover the bottle with a lid and shake until everything is thoroughly combined.
4. 4
   Loosely cover the heavy cream mixture and allow it to sit out on your kitchen counter for 12-24 hours. Ideally the temperature in your kitchen will be from 72 to 78 degrees. My apartment tends to be on the cooler side, so it always takes mine a full 24 hours to thicken. After it's at the perfect consistency, transfer it to your fridge. The creme fraiche will be good for up to 2 weeks.