Place the ginger ale
in a large, heatproof mixing bowl and set aside.
Combine the cream, milk, vanilla seeds and bean in a medium heavy saucepan and heat until mixture almost comes to a boil. Remove from the heat.
In a heatproof mixing bowl, whisk the egg yolks and sugar until frothy
colored, about 2 minutes. Whisk
1 cup of the hot cream mixture into the egg yolks in a slow, steady stream. Gradually add the egg
mixture to the hot cream and return to the heat. Cook, stirring constantly, until the mixture thickens enough to coat the back of a spoon, about 5 minutes.
Remove from the heat and strain through a fine mesh strainer
into the ginger ale. Stir to combine, then immediately transfer bowl to an ice bath, stirring frequently until cool. Refrigerate until well chilled, about 2 hours.
Pour mixture into an ice cream
maker and freeze according to the manufacturer's instructions. Transfer to an airtight container and freeze until ready to serve.
Yield: about 1 quart