Pour juice into a saucepan.
Sprinkle gelatin on the surface of the juice and allow to sit for a few seconds. This is called 'blooming the gelatin' (so you don't get lumps)
Whisk gelatin and juice together and let sit for a few minutes
Turn the stove on and heat the juice/gelatin mixture over medium heat, until gelatin is dissolved and mixture is heated through.
Turn off heat and add in sweetener and extract if using and stir.
Pour mixture into a glass bowl, dish, jello molds...whatever you want!
Put in refrigerator for 3-4 hours (or overnight)
Enjoy your delicious treat!