Preheat the oven to 350°F.
Spray and line a 9 x 13 baking pan with parchment paper.
MAKE THE CRUST
In a bowl, combine graham cracker crumbs, melted unsalted butter, brown sugar, and salt. Press the crust into the bottom of a 9x13 pan and pack it in tightly. Set aside.
MAKE THE CHEESECAKE FILLING
Using a stand mixer with a paddle attachment or handheld beater, add cream cheese and sugar to the bowl and beat on medium speed until it is creamy and smooth. Scrape down the sides of the bowl.
Then add the eggs, cornstarch, sour cream, vanilla extract, and salt and mix until creamy and smooth again. Scrape down the sides of the bowl as necessary to make sure everything is incorporated and there are no clumps.
MAKE THE PUMPKIN PIE FILLING
Add the pumpkin puree, sweetened condensed milk, eggs, cinnamon, ginger, nutmeg, and salt into a bowl.
Whisk all together until combined and smooth.
ASSEMBLE AND BAKE
Pour the cheesecake batter over the crust and spread evenly. Then pour the pumpkin pie batter gently on top of the cheesecake batter making sure to pour it across the surface. Spread evenly.
Bake for about 40 to 45 minutes in the center rack of your oven. If using a hot water bath, place a deep tray in the oven that is big enough to fit the cake pan. Place the pan in the center and pour hot water into the tray.
After the baking time, the center will appear to be a bit wobbly and that's normal. Turn off the oven and crack the door open and let the cheesecake rest for 1 hour in the oven. Then take out of the oven and allow it to cool to room temperature before popping in the fridge for a few hours until chilled completely.
Once chilled, take out of the pan and remove the parchment paper. Cut into squares, making sure to clean the knife after every cut. Enjoy!