Place cream in a heavy saucepan over medium heat. Split the vanilla bean lengthwise. Scrape seeds and add the seeds and pod to the cream. Bring to simmer. Remove from heat. Cover and let stand 1 hour to let flavors marry.
Whisk yolks and sugar in medium bowl to blend. Bring cream mixture to simmer over medium-low heat. Gradually whisk hot cream into yolks. Return mixture to saucepan and stir until the custard thickens and coats spoon, about 4 minutes. Do not boil.