In a large mixing bowl, beat the heavy cream with an electric mixer on high speed until stiff peaks form, about 3-4 minutes. Set aside.
In another bowl, whisk together the sweetened condensed milk, pumpkin puree, pumpkin pie spice, vanilla extract, and salt until smooth and well combined.
Gently fold one-third of the whipped cream into the pumpkin mixture to lighten it, then carefully fold in the remaining whipped cream until just combined. Be careful not to overmix or you'll deflate those beautiful air bubbles!
If using crushed gingersnaps, gently fold them in at this point for a delicious crunchy texture.
Pour the mixture into a 9x5-inch loaf pan or freezer-safe container. Cover tightly with plastic wrap, pressing it directly onto the surface to prevent ice crystals.
Freeze for at least 6 hours or overnight until firm. Let sit at room temperature for 5 minutes before scooping for the perfect creamy texture.