In a small saucepan, combine cream and vanilla bean paste; heat over medium-low heat, stirring frequently, just until steaming. (Do not boil.) Slowly add half of cream mixture to sugar mixture, whisking constantly. Add sugar mixture to remaining cream mixture in pan, and cook, whisking constantly, until thickened and an instant-read thermometer registers 185°F (85°C), 2 to 5 minutes. Use immediately.