01 -
Set 16 one-ounce plastic shot cups on a rimmed baking sheet. This makes the filled cups easier to carry to the refrigerator.
02 -
Add the lime gelatin powder to a heatproof bowl. Pour in the boiling water and whisk for about 2 minutes, until completely dissolved.
03 -
Stir in the cold water and let the mixture stand for 2 minutes so it is hot but no longer steaming hard.
04 -
Whisk in the vanilla vodka, peppermint schnapps, and green gel food coloring if using. Keep the color bright but not muddy.
05 -
Pour the mixture into the shot cups, dividing it evenly. Cover with lids or plastic wrap.
06 -
Refrigerate for at least 4 hours, or overnight, until the shots are fully set and jiggle as one piece.
07 -
Right before serving, top each shot with whipped cream and one red heart sprinkle. Serve cold and label the tray for adults only.