Place grapes in a bowl and cover with champagne. Allow to marinate refrigerated for 12+ hours.
Drain grapes, toss in sugar and freeze 2 hours.
Notes
You can substitute champagne with moscato or prosecco if you prefer.
How to Store
Room Temperature - You can leave these out for up to 24 hours but of course they won't stay frozen for very long! They are good either way, though.
Refrigerator - You can store your refrigerated grapes before (and after) serving for up to 48 hours. This means a total of up to four days refrigerated.
Freezer - Store your Prosecco grapes in the freezer in an airtight container or ziploc bag for up to a month.