Open up the box of purple Jello and follow the directions on the box for making it using the quick set method. Reserve ⅓ of the Jello liquid you make to use later to make the cream. Pour the rest into your cups.
Put in the refrigerator to set for 20-25 minutes. While the purple layer is setting you can get the cream layer ready. Use the jello you set aside and add ⅓ a cup of cool whip. Mix until blended.
Pour in approximately a tablespoon of cream per cup or you will run out of cream. Pour the spoonful of cream into the cup and tilt it around so it covers the Jello completely.
After you add your cream layer, put all the cups back in the refrigerator so the cream layer can set. This takes between 15-20 minutes. You will need to put cups in the refrigerator to set after adding every new Jello color and after each color of cream.
Repeat for each color of Jello that you will be using.
Video
Notes
Make sure the cream has fully set before pouring your next layer of Jello on top. Even when the cream is set, be careful when adding the Jello to the cup. Pour it slowly and distribute it evenly to avoid creating a hole in the cream layer, which could cause bits of cream to float into your next layer.
If you notice any bubbles on top of your cups, be sure to pop them before placing them in the refrigerator.
Additionally, be mindful not to add too much Jello at once; otherwise, there may not be enough space for all the colors and cream.
Do not use cups that are too big or you will end up using a ton of jello and cream.