1. In a blender, whirl blueberries and half-and-half until smoothly puréed. Add sugar, sour cream, lemon zest, lemon juice, and salt. Whirl until combined.
2. Pour mixture through a fine-mesh strainer into an ice cream maker (1-qt. capacity or larger). Freeze according to manufacturer's directions until mixture is firm enough to scoop.
3. Serve softly frozen or freeze in an airtight container until firm enough to scoop (at least 3 hours and up to 1 week).
Note: Nutritional analysis is per 1/2-cup serving.