Whisk together first 3 ingredients in a large heavy saucepan. Cook over medium heat, whisking constantly, 8 to 10 minutes or until mixture thickens slightly.
Remove from heat, and whisk in cream cheese and vanilla bean paste until cheese is melted. Cool completely (about 1 hour), stirring occasionally.
Place plastic wrap directly on mixture (to prevent a film from forming), and chill 8 to 24 hours.
Pour mixture into freezer container of a 1 1/2-qt. electric ice-cream maker, and freeze according to manufacturer's instructions. (Instructions and times may vary.)
Transfer ice cream to an airtight container. Freeze 4 hours before serving.