From "The Best Ice Cream Maker Cookbook Ever" by Peggy Fallon
Recipe Introduction
"Using whole vanilla beans instead of liquid extract makes this rich ice cream a vanilla lover's dream. Look for beans that are plump, moist, and pliable. Tiny black seeds, which look almost like powder, are released from the vanilla bean pods to make the specks that embellish the finished ice cream and lend it such a deep true vanilla flavor."
Using the pointed tip of a sharp knife, split the vanilla beans in half lengthwise and scrape the tiny black seeds into a heavy medium saucepan. Add the vanilla bean pods, cream, and milk and bring to a simmer over medium heat. Remove from the heat, cover, and let stand 30 minutes at room temperature to blend the flavors. Add the sugar and cook over medium heat, stirring, until the sugar dissolves and the mixture is hot, 6 to 8 minutes.
Whisk the egg yolks in a medium bowl. Gradually whisk in about 1 cup of the warm vanilla cream. Return the egg mixture to the saucepan, reduce the heat to medium-low, and cook, stirring, until the custard thickens enough to coat the back of a spoon (at least 160° F on a candy thermometer), 5 to 10 minutes. Do not boil or the egg yolks will curdle.
Strain the custard into a bowl, pressing through as many of the vanilla seeds as you can. Remove the vanilla bean pods from the strainer and add to the custard for flavor. Partially cover and let cool one hour at room temperature.
Refrigerate, covered, until very cold, at least 6 hours or as long as three days.
Discard the vanilla bean pods. Pour the custard into the canister of an ice cream maker and freeze according to the manufacturer's directions. Transfer to a covered container and freeze at least 3 hours or as long as three days.