Combine the cream and the milk in a large heavy saucepan. Scrape the vanilla bean 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. Add the white chocolate to the custard, and 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 the custard through a fine-mesh sieve into a heatproof medium bowl. Cover the mixture 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.
Remove from ice cream machine and fold in the broken pralines. Place in the freezer and freeze until frozen, about 2 hours.