1In a pot, combine Coca-Cola, cherry Jell-O mix, and unflavored gelatin. Sprinkle both powders on top of the soda and allow to sit for 2 minutes to bloom.
2Bring the mixture to a boil, whisking constantly until dissolved.
3Remove from heat and add white rum. Whisk to combine.
4Once slightly cooled, grease the silicone mold with nonstick spray and place it onto a baking sheet.
5Pour the mixture halfway into each heart-shaped mold cavity, then add a maraschino cherry to each.