Place the jello shot cups onto a baking sheet for easy moving to the refrigerator.
In a medium saucepan, bring 2 cups of water to a boil.
Remove from the heat and whisk in berry blue jello mix.
Add 1 cup cold water and 1 cup vodka, whisk again.
Pour into plastic shot cups, filling about ⅓ full. Discard any extra blue jello.
Move to the refrigerator to chill for 2 hours.
Next, in a medium saucepan, bring 2 cups of water to a boil.
Remove from the heat and add sweetened condensed milk. Whisk, then add 2 packets of knox gelatin. Whisk again until well combined.
Add white jello layer to the shot cups, filling to about the ⅔ full point, making sure to leave enough room for the red layer. Discard any extra white jello mixture.
Move back to the refrigerator to chill for 2 hours.
Finally, in a medium saucepan, bring 2 cups of water to a boil.
Remove from the heat and whisk in cherry jello mix, stirring until dissolved.
Add 1 cup cold water and 1 cup vodka. Whisk again.
Add to the shot cups for the final layer. Discard any extra jello you don’t need.
Move back to the refrigerator to chill a final time, for 2 hours.
Before serving, top with whipped cream and a maraschino cherry.