To prepare the crust, mix the graham cracker crumbs, brown sugar, cinnamon, and nutmeg until well combined.
Create a small hole in the center and add the melted butter. Stir well to combine.
Pour the mixture into a 9-inch springform pan, and pack tightly. You can use a flat bottom measuring cup.
In a medium bowl with a hand mixer, whisk the whipping cream into stiff peaks and set aside. This should only take 3-4 minutes.
In a large bowl beat the cream cheese until smooth.
Add in the pumpkin puree and beat again until smooth and no lumps.
Slowly to start, beat in the powdered sugar, pumpkin spice, vanilla and sea salt until well mixed.
Slowly fold in the whipped cream, being careful not to lose all the air.
Pour the filling on the crust and try to create a smooth even top layer. If you have a dough scraper you can get a nice clean surface by running it in circles inside the pan. Refrigerate at least 8 hours or overnight. You may want to add parchment paper underneath for easy clean up later.
Slide a knife along the edges to loosen the crust and remove the cheesecake from the springform pan.