Grease the inside of each plastic shot cup with cooking spray.
Heat 2 cups of water until boiling.
Pour the boiling water into a mixing bowl with the Jell-O powder and whisk until powder is completely dissolved. Pour in the vodka and remaining cold water and whisk. Fill each shot cup with the Jell-O mixture and refrigerate for 1-2 hours until firm.
Just before serving, top each Jell-O shot with whipped cream and sprinkles.