Truly Incredible Buttermilk Ice Cream

In a heavy saucepan, bring the cream to a simmer, stirring frequently. In a medium bowl, whisk the egg yolks with sugar. Whisk about 1 cup of the simmering cream into the egg mixture until well blended; stir back into the hot mixture in the saucepan. Cook, stirring constantly, over medium heat until slightly thickened, about 5 to 7 minutes. Do not let the mixture boil. Remove from heat and stir in the cold, well-shaken buttermilk and vanilla extract. Put the mixture in an ice bath or refrigerate the mixture until very cold, about 2 hours. Freeze in your ice cream freezer following manufacturer's directions. Transfer to a container and cover tightly. Freeze the ice cream until firm. Makes about 1 quart of ice cream.