Instructions

Combine the cream and 1 cup of the milk in a large heavy saucepan. Scrape the seeds into the cream mixture and add the bean pod. Bring to a gentle boil over medium heat.
 
Whisk the yolks and sugar in a medium bowl. In a slow and steady stream, whisk 1 cup of the hot cream mixture into the egg mixture. Gradually whisk the egg mixture back into the saucepan. Stir constantly over medium-low heat until the mixture thickens enough to coat the back of a spoon and reaches 170 degrees F on an instant-read thermometer, about 5 minutes. Strain through a fine- mesh sieve into a heatproof medium bowl.
 
Stir in the remaining 1 cup milk into the ice cream base and cover with plastic wrap, pressing the wrap against the surface of the custard to prevent a skin from forming. Refrigerate until well chilled, at least 2 hours.
 
Pour the chilled custard into an ice cream machine. Churn according to the manufacturer's instructions. Pack into an airtight container and freeze until ready to serve.