Add the cold water and your choice of apple vodka or sour apple schnapps to the bowl, giving everything a good stir to combine. The mixture should be smooth and uniform in color with no separation between the liquids.

Carefully fill each 2-ounce shot cup about three-quarters full with your jello mixture. Leaving that little bit of room at the top makes them easier to eat and gives you space for garnishes if you want to dress them up.

Transfer the filled shot cups to your refrigerator and let them chill for at least 2 hours until they're completely set. They should jiggle when you tap them but hold their shape firmly – if they're still liquidy at all, give them more time.

When you're ready to serve, add a dollop of whipped topping and a thin slice of green apple to each shot if desired. Don't add these garnishes ahead of time though, as the whipped cream can break down and the apple slices will brown.