Step 1: Crush the gingersnap cookies. Place them in a large freezer bag and crush with a rolling pin, or pulse in a food processor, leaving some small pieces for texture. Set aside 2 cups for layering and a small amount for garnish.
Step 2: In a large mixing bowl, beat the softened cream cheese with the powdered sugar and vanilla extract until smooth and creamy, about 2-3 minutes.
Step 3: In a separate, chilled bowl, whip the very cold heavy cream until stiff peaks form.
Step 4: Gently fold about one-third of the whipped cream into the cream cheese mixture to lighten it. Then, carefully fold in the remaining whipped cream until just combined, ensuring no streaks remain.
Step 5: In another mixing bowl, combine the pumpkin puree, granulated sugar, pumpkin pie spice, and a pinch of salt. Mix until well combined and smooth.
Step 6: To assemble the trifle, spoon half of the crushed gingersnap crumbs evenly across the bottom of a large (3-4 quart) trifle bowl.
Step 7: Carefully spread half of the pumpkin mixture over the gingersnap layer.
Step 8: Gently spread half of the cream cheese mixture over the pumpkin layer.
Step 9: Repeat the layers: add the remaining gingersnap crumbs, followed by the remaining pumpkin mixture, and finally, the rest of the cream cheese mixture.
Step 10: Cover the trifle loosely with plastic wrap and refrigerate for at least 4 hours, or preferably overnight, to allow the flavors to meld and the cookies to soften.
Step 11: Before serving, garnish with extra gingersnap crumbs, whole cookies, or a dusting of cinnamon, if desired. Serve chilled.