- 2 cups heavy cream (try to find cream that is not ultra-pasteurized)
- ½ cup sour cream (or 2 tablespoons buttermilk)
- In a clean jar, combine heavy cream and sour cream. Stir to mix.
- Cover the jar lightly with plastic wrap and let sit unrefrigerated for 8-24 hours. (Ideally you want a location that is between 65 and 75 degrees F so the cultures will grow and the cream will thicken. If your room is cool, the process will take closer to 24 hours.)
- Stir again and refrigerate before using.
- Store covered for up to 1 to 2 weeks in the refrigerator.