Pour cream and buttermilk into a lidded jar. Replace lid, shake, and let mixture rest at room temperature 6 to 8 hours. Refrigerate at least 24 hours; mixture reaches optimal thickness after 4 to 5 days. In a large metal bowl, whip refrigerated cream, sugar, and vanilla with a balloon whisk until it achieves the consistency of whipped cream. Source: "Martha Stewart Living Magazine, Jul/Aug 1997" S(Formatted for MC5): "by Lynn Thomas - Lynn_Thomas@prodigy.net" Per serving: 1302 Calories (kcal); 133g Total Fat; (90% calories from fat); 11g Protein; 20g Carbohydrate; 494mg Cholesterol; 260mg Sodium Food Exchanges: 0 Grain(Starch); 0 Lean Meat; 0 Vegetable; 0 Fruit; 26 1/2 Fat; 1/2 Other Carbohydrates Recipe by: Martha Stewart Converted by MM_Buster v2.0n.