1 pint good quality cream (never use ultra-pasturized or UHT cream)
1 tablespoon cultured buttermilk (store or home) or creme fraiche from a previous batch
Place cream in clean glass container. Add buttermilk or creme fraiche, stir well, cover tightly, and place in a warm spot for 20-24 hours. Then chill well.
It has a mild but delicious flavour and is wonderful in creamed soups and sauces or any where you might use regular sour cream. The bonus factor is that you know it's chaulk full of healthy enzymes and doesn't have one preservative or thickener in it!