* Note; Two (14-ounce) packages frozen raspberries, thawed, may be substituted for fresh raspberries.

Stir together raspberries and sugar in a bowl; let stand 30 minutes.

Process raspberry mixture in a food processor or blender until smooth, stopping to scrape down sides. Pour through a fine wire-mesh strainer into a 9-inch square pan, discarding solids; stir in buttermilk. Cover and freeze 8 hours.

Break frozen mixture into chunks, and place in bowl; beat at medium speed with an electric mixer until smooth. Return to pan; cover and freeze 3 hours or until firm. Garnish, if desired.