In a small saucepan over moderate heat, add the nectar, pear liqueur and star anise. Bring up to a boil and turn heat off. Allow to steep for 5 minutes, then discard the star anise. Cool to room temperature and chill until ready to use.
To serve, drop 1 cranberry to the bottom of each champagne coupe or flute. Add 2 tablespoons of the spiced pear mixture for coupe glasses and 3 tablespoons for the flute glasses. Top with Prosecco and enjoy!