Place the graham crackers inside a large resealable plastic bag.
Crush them thoroughly with a rolling pin until the pieces become very fine and resemble coarse sand.
Transfer the crushed graham crackers to a medium mixing bowl.
Pour in the melted butter and stir until the crumbs are evenly coated and the mixture is thoroughly combined.
Set the prepared crust mixture aside.
Add the unflavored gelatin, cinnamon, ginger, nutmeg, and salt to a heavy-bottomed saucepan and combine.
Pour in the heavy cream, then add the granulated sugar and beaten eggs. Stir well until the mixture is uniform.
Cook over low heat while stirring continuously. Continue cooking until the gelatin has completely dissolved and the mixture has thickened, approximately 10 minutes.
Remove the saucepan from the heat once the filling has thickened, then stir in the pumpkin purée until evenly incorporated.
Spoon a portion of the graham cracker mixture into the bottom of each serving cup.
Press the crumbs down gently to form a compact, sturdy crust layer.
Distribute the pumpkin filling over the prepared graham cracker bases.
Cover each cup with foil and refrigerate for at least 2 hours, or until the pumpkin filling has fully set.
Remove the chilled pumpkin pie cups from the refrigerator when ready to serve.
Finish each portion with a dollop of whipped cream, if desired.
Serve immediately while chilled.