1. Combine berries, sugar and lemon juice in a food processor; process until smooth. Add yogurt and pulse until mixed in. If using fresh berries, transfer the mixture to a medium bowl, cover and refrigerate until chilled, about 1 hour.
2. Transfer the berry mixture to an ice cream maker and freeze according to manufacturer's directions. (Alternatively, freeze the mixture in a shallow metal pan until solid, about 6 hours. Break into chunks and process in a food processor until smooth and creamy.) Serve immediately or transfer to a storage container and let harden in the freezer for 1 to 1 1/2 hours. Serve in chilled dishes.

Yield: 6 servings