How to Make It
Whisk together first 5 ingredients in a heavy saucepan. Cook over medium-low heat, whisking constantly, 8 to 10 minutes or until mixture reaches a chilled pudding-like thickness. Remove from heat; stir in vanilla. Cool to room temperature (about 1 hour). Place plastic wrap directly on mixture (to prevent a film from forming), and chill 6 to 24 hours.