Using a stand or hand mixer, whip cream and sugar until a soft peak forms. Transfer to another bowl and set aside.
Add cream cheese and brown sugar to the mixing bowl and beat until completely smooth, scraping down the bowl a few times during the process.
Add pumpkin and spices to the cream cheese. Mix until incorporated.
Using a spatula, gently fold 1/3 of the whipped cream into the pumpkin mixture. Be gentle; you want to keep as much air in the cream as possible. Set aside.
Place half of the ginger snaps in the bowl of a food processor and process until you have chunky crumbs. Don’t over-process; you want to keep some texture and crunch. Set aside.
Add 1/8 of the pumpkin mixture to the bottom of each of four glass.
Next add 1/8 of the whipped cream.
Add another layer of pumpkin, followed by another layer of whipped cream.
Sprinkle the top layer with the ginger snap crumbs.
Finally, top each cup with a whole ginger snap cookie. (If you are not serving the mousse right away, wait until just before serving to add the crumbs and cookies, otherwise they will get soggy.)
Serve immediately or refrigerate until ready to serve. Enjoy!