If using frozen berries set out to thaw, usually around an hour
Combine the heavy cream and mascarpone until smooth, use a hand mixer if necessary, but this can be done by hand with a little elbow grease, and set aside
Purée the berries, I used a handheld immersion blender, and pass through a fine mesh strainer to remove all the seeds
Combine the powdered erythritol and raspberry purée until smooth
Combine the berry mixture and the dairy mixture and refrigerate for several hours or overnight
Churn in your ice cream maker and serve immediately for soft serve texture or after an hour in the freezer for a firmer texture.