For The Juice: Place seeds in a heavy-duty zip-top plastic bag; seal, pressing as much air as possible out of bag. Gently mash seeds with a rolling pin or bottom of a bottle.
Place mashed seeds, juice, and water in a medium nonreactive saucepan and bring to a boil. Cook 10 minutes. Strain mixture through a sieve into a bowl; discard solids.
Stir all ingredients over ice to chill and strain into a pre-chilled cocktail glass. Top with champagne.
Recipe by 50 Campfires at https://50campfires.com/3-sun-kissed-cocktails/