In the bowl of an electric mixer, mix together on low speed: the cream cheese, sugar, and flour until combined. Be sure to scrape the sides and bottom of the bowl if needed.
Next, add the pumpkin puree, vanilla extract and the first egg and beat slowly until mostly combined. Then add the remaining egg and mix until well combined, still mixing everything on low speed. Now, add the sour cream and spices and continue mixing until combined.
Change mixer attachment to a whisk and beat on medium-high speed for 5 minutes or so until completely smooth and lump-free.
Pour the batter into the prepared pan until 3/4 filled. NOTE: Leaving a bit of room at the top prevents the cheesecake from spilling over while baking.
Bake the cheesecake for 35-40 minutes (until center comes out mostly clean when tested with a toothpick or knife), then turn off the oven and allow it to sit in the oven for another 5 minutes with the oven door halfway open to avoid cheesecake from deflating. NOTE: When baking, I always prepare a medium pot with water and add it to the oven as well, to keep cheesecake temperature even and to add moisture.
Once done, remove the cheesecake from the oven and allow it to continue to cool for another 15-20 minutes, before putting it in the refrigerator for at least an hour. Once cheesecake has fully chilled, top with whipped cream, and crumbled Biscoff cookies. Slice and enjoy.