2 10-ounce packages frozen raspberries in syrup, thawed
1 12-ounce can frozen lemonade concentrate, thawed
3 750-ml bottles chilled Prosecco
Fresh raspberries
Lemon slices
Puree raspberries in blender or processor until smooth. Strain into 2-cup pitcher, discarding seeds. Pour thawed lemonade concentrate into another 2-cup pitcher. (Raspberry puree and lemonade concentrate can be prepared 1 day ahead. Cover and refrigerate.)
Place pitchers with lemonade concentrate and raspberry puree onto table with champagne flutes and Prosecco. Pour 2 to 4 tablespoons raspberry puree or lemonade concentrate into each Champagne flute (amount will depend on size of glass and personal preference). Slowly fill flutes with Prosecco. Garnish with fresh raspberries or lemon slices.
