
Simmer first four ingredients uncovered, stirring occationally. Continue to cook until thickened and reduced by 2/3 (about 20 minutes.)
Pour this mixture into a fine sieve over a measuring cup and let stand for five minutes. DO NOT press the solids. Chill the syrup, covered, until cold.
Divide the Prosecco into six glasses and add 1 1/2 tsp of syrup. Enjoy!
Remaining syrup will keep for three days.