How to Make It
Bring first 6 ingredients to a boil in a large saucepan over high; cook 10 minutes or until cranberries begin to burst, stirring occasionally. Remove pan from heat; cool to room temperature. Place in an airtight container, and refrigerate 2 hours or overnight. Strain cranberry mixture through a fine-mesh sieve over a bowl, pressing solids with back of a spoon. Discard solids. Package for gifts, or continue with recipe.
To prepare each cocktail, combine 1/2 cup prosecco and 3 tablespoons shrub in an ice-filled shaker; stir. Strain into a martini glass.