1 pint heavy cream
starter of choice: 1 heirloom buttermilk starter or 2 tbsp cultured buttermilk,
yogurt or kefir
Combine heavy cream and starter in a clean 1-quart jar. Cover jar with butter muslin cloth and secure muslin with a rubber band. Let stand at room temperature for 1-3 days or until thickened. Stir and refrigerate. The cream will continue to thicken and develop flavor in the refrigerator, where it will keep for about two weeks.