Preheat your oven to 350 degrees.
Place the ginger snap cookies in a food processor and pulse until they become coarse crumbs. In a medium bowl, melt the unsalted butter. Combine the ginger snap crumbs, sugar, salt, and melted butter, mixing well.
Line a 9-inch springform pan with parchment paper and wrap the outside with aluminum foil to prevent leaks. Press the ginger snap crust mixture into the bottom and up the sides of the pan. Bake in the preheated oven for 10 minutes.
Once the crust is done, transfer it to a wire rack and increase the oven temperature to 400 degrees.
In the bowl of a stand mixer fitted with the paddle attachment, combine the cream cheese and sugar. Mix on medium speed until smooth, scraping down the sides of the bowl as needed.
Add the heavy cream, sour cream, and pumpkin puree to the cream cheese mixture. Mix until well combined. Gradually add the eggs, one at a time, followed by the vanilla extract, salt, pumpkin pie spice, and cornstarch. Mix on medium speed for 1 minute, ensuring everything is thoroughly incorporated.
Pour the cheesecake filling into the prepared crust. Tap the pan on the counter a few times to remove any air bubbles.
Place the springform pan inside a larger pan with tall sides. Put the larger pan in the oven and carefully fill it with water to create a water bath.
Bake the cheesecake for 10 minutes at 400 degrees. Then, reduce the oven temperature to 250 degrees and continue baking for an additional 1 hour and 15 minutes. Turn off the oven and leave the cheesecake inside with the door closed for 30 minutes, followed by another 30 minutes with the oven door slightly ajar.
Cover the cheesecake and refrigerate it for at least 8 hours or overnight. Once chilled, gently release the cheesecake from the springform pan by running a butter knife along the edges.
Before serving, top the cheesecake with whipped cream and crushed ginger snap cookies.