Whip the Cream: In a large mixing bowl, whip the heavy cream with a hand mixer or stand mixer until soft peaks form. Gradually add in the powdered sugar and vanilla, continuing to whip until stiff peaks form.
Mix Pumpkin Base: In another bowl, combine the pumpkin puree, pumpkin pie spice, and a pinch of salt. Stir well until blended and smooth.
Combine: Gently fold the whipped cream into the pumpkin mixture using a spatula. Be careful not to deflate the whipped cream—this will keep your mousse light and airy!
Chill: Once combined, transfer the mousse into individual serving cups or a large bowl. Cover with plastic wrap and refrigerate for at least 2 hours to set properly.
Serve: Before serving, top with whipped cream and a sprinkle of gingersnap crumbs for a delightful crunch.