Place the first 4 ingredients in blender and process on low until smooth. Pour mixture into a medium saucepan and cook over low heat, stirring constantly, until bubbles form around the edge of the mixture. Do not overcook. Chill until room temperature.
Pour mixture into ice cream maker. Stir in cream and vanilla, then add artifical sweetener. Freeze according to ice cream maker instructions.
Note
Amount at 4.5 grams per 1/2 cup serving.
This recipe for Frozen Chocolate Custard serves/makes 1qt