1. Heat oven to 350°F (175°C). Line the bottom of a 9-inch (23 cm) springform pan with parchment. Wrap the outside of the pan in two layers of heavy foil (for an optional water bath later).

2. Make the crust: In a bowl, mix crumbs, melted butter, sugar, and a pinch of salt until evenly moistened. Press firmly into the bottom of the pan. Bake 8–10 minutes; cool while you prepare the filling. Reduce oven to 325°F (165°C).

3. Make the filling: In a large bowl, beat cream cheese until perfectly smooth (no lumps). Add brown sugar and granulated sugar; beat until creamy. Mix in pumpkin purée, vanilla, cornstarch, spices, and salt. Beat in eggs one at a time on low speed just until incorporated (avoid over-mixing).

4. Bake: Pour filling over the crust. Bake at 325°F (165°C) for 55–65 minutes (edges set, center still slightly wobbly). For extra insurance, bake in a water bath: place the wrapped pan in a larger pan and add hot water halfway up the sides.

5. Cool & chill: Turn off oven, crack the door, and let cheesecake rest 30 minutes. Remove, run a thin knife around the edge, then cool 1 hour at room temp. Chill uncovered 4 hours or overnight until fully set.

6. Ganache: Heat cream to steaming (not boiling), pour over chopped chocolate, rest 1 minute, then stir from center until glossy. Stir in corn syrup if using. Pour over chilled cheesecake; tilt pan for an even coating.

7. Spiderweb: While ganache is still fluid, pipe 6–7 concentric circles of sour cream (or white chocolate). Drag a toothpick from center outward in straight lines to form a web. Chill 15 minutes to set. Release from pan, slice with a hot wiped knife, and serve.