Add gelatin and water to a medium saucepan and allow to sit for one minute. Then, heat over medium heat, whisking until gelatin is completely dissolved.
Mix in pumpkin, sugar, and pumpkin spice, whisking until fully dissolved.
Remove from heat and stir in vodka and heavy whipping cream.
Pour into shot glasses and allow to sit for 20 minutes at room temperature, then refrigerate until fully set (at least 4 hours).
Before serving, top with whipped cream and pumpkin candies, if desired.
Notes
This recipe will make enough for 12 small (2 oz) plastic jello shot cups. If using large glass shooters as shown it will make enough for about 4.