Preheat your oven to 350°F (175°C). In a food processor, blend Biscoff cookies into fine crumbs. Combine the crumbs with melted butter and a pinch of pumpkin spice in a bowl, mixing until moistened. Firmly press this mixture into the bottom of a 9-inch springform pan to create a solid crust. Bake for 8-10 minutes until fragrant, then allow it to cool slightly.

In a large mixing bowl, beat the cream cheese with an electric mixer on medium speed until smooth and creamy. Gradually add white sugar and brown sugar, mixing until fully combined. Incorporate the pumpkin puree and pumpkin spice, blending until the mixture is velvety. Add eggs one at a time, mixing well after each addition, followed by the vanilla, sour cream, and heavy cream, ensuring everything is well combined.

Carefully pour the smooth filling over the cooled crust, using a spatula to smooth the top for an even finish. For a water bath, wrap the springform pan with aluminum foil to prevent leaks. Place the wrapped pan into a larger roasting pan and fill it with hot water halfway up the sides of the springform pan, which helps keep your pumpkin cheesecake creamy.

Lower the oven temperature to 300°F (150°C) and carefully place the roasting pan in the oven. Bake for 50-70 minutes, until the edges are set but the center still jiggles slightly when shaken. Once baked, turn off the oven and leave the cheesecake inside with the door ajar for an additional hour, allowing it to cool gradually and minimizing cracks.

After cooling in the oven, let the cheesecake sit at room temperature for around 30 minutes. Then, transfer it to the refrigerator and chill for at least 4 hours or, ideally, overnight to allow it to fully set and enhance the flavors of your rich pumpkin cheesecake.

When ready to serve, whip the chilled heavy cream in a mixing bowl with powdered sugar and a sprinkle of ground cinnamon until stiff peaks form. Gently spread or pipe the whipped cream over the chilled pumpkin cheesecake, creating a beautiful finish, and optionally sprinkle with ground cinnamon or crushed Biscoff cookies for an elegant touch.