Chilled Berry Soup

1 1/2 c water
1/2 c sugar
1 cinnamon stick
2 t cornstarch
1/4 c water
1 6-oz can frozen lemonade
1 quart buttermilk
1 quart or more berries – blueberries, blackberries, raspberries (1 quart = 2 pints)
1 c blueberry or raspberry yogurt

Boil water with sugar and cinnamon stick until sugar is dissolved. Mix cornstarch with 1/4 c water and stir into mixture, stirring until clear. Remove from heat and add frozen lemonade, buttermilk, and blueberries. Smash some of the blueberries with the back of your spoon to release color, or puree some in your food processor before adding to mixture. Stir in yogurt. Serve with a dollop of whipped cream. (Leave the cinnamon stick in unused portion for added flavor.)