01 - Preheat oven to 350°F (175°C). Grease a 9-inch springform pan and line the base with parchment paper.
02 - In a bowl, combine crushed biscuits, melted butter, and sugar. Mix until evenly blended, then press into the base of the pan. Bake 10 minutes; allow to cool slightly.
03 - In a large bowl, beat cream cheese and sugar until completely smooth. Add pumpkin purée and blend thoroughly. Incorporate eggs one at a time, mixing until just combined.
04 - Mix in sour cream, flour, vanilla, cinnamon, nutmeg, ginger, cloves, and salt. Blend until mixture is silky, scraping the bowl sides as needed.
05 - Pour filling over crust, smoothing the top. Bake for 55 to 60 minutes, until edges are set and center is slightly wobbly. Turn off oven, crack door, and cool inside for 1 hour.
06 - Remove cheesecake from oven and cool to room temperature. Refrigerate for at least 4 hours or overnight for best texture.
07 - Melt chocolate with coconut oil or butter in microwave or double boiler until smooth. Transfer to a piping bag or zip-top bag, snip a tiny corner, and pipe 3–4 concentric circles on cheesecake. Drag a toothpick outward from the center to form a spiderweb, cleaning toothpick between each drag.
08 - Slice and serve well chilled.