Heat 1 cup of the champagne in a saucepan over medium heat. Cook until the mixture reduces by half.
While the champagne is reducing, stir together the remaining champagne and the gelatin. Let it sit for 5 minutes.
Whisk the sugar into the reduced champagne and add the gelatin mixture to the saucepan too. Whisk constantly with the saucepan over medium heat until the sugar and gelatin dissolve and the mixture slightly thickens. Turn off the heat.
Fill the molds with the mixture using a dropper or a small creamer to pour. Run a spatula over the molds to get off any excess champagne mixture. Stick in the fridge for about 90 minutes (or longer is fine too!). Then it's time to eat and serve! These stay great at room temp for awhile, but I wouldn't gift them as is. They are best when stored in the fridge and brought out for cocktail parties or snacks!