Add jello mix to 1 cup boiling water and stir until well dissolved. This should take around 2-3 minutes.
Add 1/2 cup cold water and 2 tbsp reserved pineapple juice.
In a separate bowl, blend cream cheese with a hand mixer.
Add jello mixture slowly, not allowing it to splash. Allow to slightly froth.
Chill until thickened - roughly 1 hour
Mix in marshmallows and crushed pineapple
Chill for 2+ hours
Serve with sprinkles, cherry and cool whip (if desired)
Enjoy!