1/2 cup sugar
2/3 cup lemon juice
3 cups frozen strawberries
1/2 cup vanilla yogurt
Combine sugar and 1/2 cup water in a medium saucepan over medium heat, stirring until the sugar has dissolved; let cool.
In a large pitcher, whisk together sugar mixture, lemon juice and 1 1/2 cups water.
Combine strawberries, yogurt, lemon mixture and 2 cups ice in blender until smooth.