Using an electric mixer, beat the cream until stiff. Set aside 2 cups of the whipped cream for serving; refrigerate until ready to use.
In a large bowl, stir together the pumpkin puree, vanilla extract, cinnamon, ginger, cloves, and salt. Fold in 1/2 of the marshmallow cream, then 1/2 of the remaining whipped cream. Repeat and fold in the remaining 1/2 marshmallow cream and remaining 1/2 of the whipped cream until combine.
In a medium bowl, sprinkle the chopped gingersnap cookies with rum.
Spoon 1/3 of the pumpkin mousse into a clear glass serving bowl, spreading evenly. Sprinkle 1/2 of the gingersnap cookie mixture on top. Spoon another 1/3 of the pumpkin mousse over the cookie mixture. Repeat with the remaining 1/2 of the remaining gingersnap cookies, then top with the final layer of pumpkin mousse. Cover with plastic wrap and refrigerate at least 1 hour and up to 4 hours.
Just before serving, top with the reserved 2 cups whipped cream and sprinkle with the crushed gingersnaps.
Makes 10 to 12 servings.
* Learn to make homemade Marshmallow Fluff/Cream.
Spiced Pumpkin Mousse Trifle Recipe: https://whatscookingamerica.net/Cake/PumpkinTrifle.htm