1 (19 ounce) can frozen cranberry juice concentrate
1 tablespoon lemon juice
1/2 cup milk
1 teaspoon lemon zest
1 cup white sugar
1 egg
1 teaspoon distilled white vinegar
6 fluid ounces lemon-lime flavored carbonated beverage
In a blender, combine cranberry juice concentrate, lemon juice, milk, lemon zest, sugar and egg. Blend until smooth, pour into a glass and top with lemon-lime soda.