Place the plastic cups on a large tray or plate and set aside.
In a large mixing bowl, add the dry pudding mix, pumpkin pie spice and ground cinnamon. Whisk to combine.
Mix in the cold milk. Add the pumpkin purée and stir well to combine.
Pour in the chilled vodka and stir to incorporate.
Spoon the pudding into the plastic cups, filling each cup halfway. Chill overnight or for at least 4 hours. After 4 hours, you can place lids on the cups if not serving right away.
Before serving, add a dollop of whipped cream and a sprinkling of cinnamon on top.
Optional – add a graham cracker quarter to each shot.