Bloom the gelatin with the Sprite in the bottom of a mixing bowl. After 5 minutes, set the bowl over a pot of simmering water to melt the gelatin, or microwave in short 5 second bursts until melted.
Use a hand or stand mixer and mix in the salt along with the powdered sugar, a cup or two at a time. Keep adding the powdered sugar until you have stiff fondant-like dough (very much the texture of Play-Doh). You may not need all of the powdered sugar.
Turn the dough out onto the counter top and knead until smooth.
Divide into as many portions as you would like colors/flavors and keep any dough you’re not currently using wrapped in plastic to prevent it from crusting over.
Knead in the colors and flavors until homogenous. Taste a pinch of the dough and add more extract or powdered fruit to suit your taste.
Roll the dough to about ⅜” thickness and cut out shapes. Alternately you can mold the dough into whatever shapes you like, just keep them on the small side so they can dry through and through.
Arrange the candies on a parchment lined sheet pan and air dry for 48 hours. After 24 hours, flip all the hearts over so they can dry on both sides. Compared to candies flavored with extracts, the ones made with freeze dried fruit won’t dry out quite as hard and will retain a slightly softer texture (they will still be crisp, just not as rock-hard as classic Conversation Hearts).