Line your cups up on a baking sheet that will fit them. No lids.

For the first layer, place your yellow jello mixture in a medium mixing bowl and add ½ cup boiling water. Mix until no graininess remains.

Add ¾ cup vodka and ½ cup cold water to the bowl. Mix well.

Using the injector, fill up each shot cup a third of the way.

Place in the fridge for an hour or until solidified.

For the second layer, repeat steps 2-4, but use the grape jello instead.

Once the purple jello has solidified, repeat steps 2-4 for the next layer using the pink jello.

Once the last layer has solidified, top with some whipped cream, if desired, and enjoy!