Using a handheld or stand mixer, whip the heavy cream to stiff peaks.
In a separate bowl, whisk together the condensed milk, vanilla, pumpkin puree, and spices. Gently fold in the whipped cream, then the crushed biscuits.
Pour the mixture into a 9x5-inch loaf pan, sprinkle with extra crushed ginger biscuits if desired, then cover tightly. Place in the freezer for at least 6 hours, or overnight before serving.