Directions:
1. In a blender container place half of the berries, soda, yogurt, frozen concentrate, and sugar. Cover; blend until berries are puréed and sugar is dissolved. Pour into a 13 x 9 x 2 in. pan. Repeat with remaining ingredients except carbonated water; pour into pan. Cover; freeze 3 hr. or until firm.
2. Use a fork to break up frozen mixture. In blender container place half of mixture and 1 c. carbonated water. Cover; blend until frothy. Pour into chilled glasses. Repeat with remaining mixture and carbonated water