1 cup whipping cream, room temperature
1/2 cup sour cream, room temperature
1 teaspoon homemade vanilla extract

Put whipping cream, sour cream and vanilla in a jar or container with a tight lid. Cover securely and shake 15 seconds. Set aside at room temperature for about an hour or two, shaking every once in a while until very thick. Cream will thicken faster if the room is warm.

Stir thickened creme fraiche well. Refrigerate before serving. Cover tightly and store in refrigerator for up to 2 weeks.